This is basically a list of mods and settings I use after picking up the game again in Q2 2020 and doing some research on recommended mods. Other modlists might be outdated or they change too much. My personal mindset is to not deviate too much from the vanilla experience. The main purpose of this list/guide is a reference to myself in case I ever lose my configurations but this list/guide may be useful for you as an inspiration/resource for your own modding. And who knows, maybe you want to use the comments section to contribute if you know better mods for the purposes listed in this guide.

For the purpose of this guide, I'm assuming all big DLC (Dead Money, Old World Blues, Honest Hearts, Lonesome Road) are installed, you know how to use a computer, you've got an account on Nexusmods, you use Vortex, you know how to install mods, and that you are sufficiently curious to check the settings/configs of the tools you use. The guide is structured, going from absolutely necessary fixes/improvements to recommended gameplay enhancements to completely optional game balance changes in both directions (harder/easier).

https://www.nexusmods.com/newvegas/mods/62552 (manual download and installation)

Purpose: Allows the game to use 4 GB of RAM instead of 2 GB. Improves stability and performance.

http://nvse.silverlock.org/ (download latest stable version)

Purpose: Helps with stability, fixes bugs, and is required for many mods.
I recommend you create \Fallout New Vegas\Data\NSVE\nvse_config.ini with the following content:
This helps with stability and preventing crashes.

https://www.nexusmods.com/newvegas/mods/66537

Purpose: Fixes microstutters and physics issues when playing the game at high FPS.

https://www.nexusmods.com/newvegas/mods/53635

Purpose: Prevents crashes.

Even after setting up the mods properly, without NVAC, my game just crashed when I went into VATS. After setting up NVAC, my game pretty much never crashed again.

https://www.nexusmods.com/newvegas/mods/51664

Purpose: This fixes a whole lot of issues with the game. It also makes some balance changes. Essentially the ultimate unofficial patch for New Vegas.

Keep in mind that YUP makes the following balance changes that might be relevant/important to your game experience:

• The infinite casino chips to caps exploit (dropping 32769+ casino chips, picking them up, then turning them in endlessly) will no longer work. Picking them up will remove them from your inventory but you will not have the dialogue option to turn them in. I'm not 100% sure if YUP is responsible for this but I've never bothered to test it. If you know better, feel free to correct me in the comments.
  
• The "equip slots" of headgear are changed to allow you to equip item combinations that do not cause any visual conflict but would be otherwise impossible in the vanilla game. For instance, a radii accentuator + a beret + glasses + a rebreather/breathing mask...
  
• The Fast Times perk (gained from consuming Turbo 20 times) now has an effect on Implant GRX, extending its duration by 33%. With rank 2 of Implant GRX, the Chemist perk, and the Day Tripper perk (gained from consuming addictive drugs 25 times), the duration of Implant GRX will be extended to a whopping 10.6 seconds (30.3 seconds from the player's perspective).
  
• The damage output of Gauss Rifles will now take the enemy's resistance to energy weapons into account, this makes them a bit less OP. Although I personally disagree with this as it doesn't make any logical sense, this is part of the mod.

https://www.nexusmods.com/newvegas/mods/65412 (download main file as well as Unofficial Patch NVSE - Pyromaniac Effect Bonus)

Purpose: Fixes lots of bugs that require NVSE or didn't make it into YUP.

https://www.nexusmods.com/newvegas/mods/58277

Purpose: Extends NVSE, adds new functions, includes numerous bugfixes/tweaks and restores several broken game features.

https://www.nexusmods.com/newvegas/mods/66347 (download main file as well as Stewie Tweaks INI)

Purpose: Adds a yuge amount of engine-level game tweaks and can be configured extensively.

I use a lot of custom settings for this and I'm listing those in the later sections of the guide.

https://www.nexusmods.com/newvegas/mods/42507

Purpose: Brilliant way of configuring many mods.

https://www.nexusmods.com/newvegas/mods/59149

Purpose: Improves collision meshes.

Load Collision Meshes FNV after YUP.

https://www.nexusmods.com/newvegas/mods/65052

Purpose: Improves weapon meshes and fixes lots of weapon bugs.

Load WMMI after YUP.

https://www.nexusmods.com/newvegas/mods/57174
https://www.moddb.com/mods/vanilla-ui-plus (drop archive into Vortex window)

Purpose: Improves the UI of the game while keeping the original look & feel intact. UIO is necessary for the installation of VUI+.

Load VUI+ after YUP.

https://www.nexusmods.com/newvegas/mods/67277

Purpose: Reduces/removes the amber tint from the game while maintaining a mostly "vanilla" look.

https://www.nexusmods.com/newvegas/mods/43135 (load version of your choice together with NMC New Vegas Patch for ALL Sized packs)

Purpose: Improves the textures of the game without changing the artstyle too much.

Load the NMCs Textures NV pack of your choice after YUP.
Load NMC New Vegas Patch for ALL Sized packs after the texture pack of your choice.

https://www.nexusmods.com/newvegas/mods/55334

Purpose: Lets you see your body and shadows when in 1st person. Forced 3rd person situations (e.g. death or sitting down) are now in 1st person.

https://www.nexusmods.com/newvegas/mods/68084 (download main file together with Container Animations)

Purpose: Gives you container looting UI similar to the one in Fallout 4 or 76.

Load Just Loot Menu - Container Animations after Collision Meshes FNV.

https://www.nexusmods.com/newvegas/mods/50468

Purpose: Gives you nice UI elements for managing companions.

Keep the following things in mind:

• This mod allows you to have many companions at once without abusing any glitches/exploits
  
• In the Sierra Madre, you are only allowed to have one SM-specific companion at once
  
• When entering the Sierra Madre from the abandoned BoS bunker, your active companions won't be auto-dismissed, meaning that they are on standby while you are in the Sierra Madre, letting you keep using their companion perks
  
• When entering the Big Mountain through the Midnight Science Fiction Feature! quest, your companions will be dismissed automatically
  
• You must dismiss your companions manually before you can travel to Zion/the Divide

https://www.nexusmods.com/newvegas/mods/65584

Purpose: Changes the look of the Pip-Boy world map to indicate locations surrounded by invisible walls, letting you know whether your exploration is going to be fruitless before you smash into one of those.

https://www.nexusmods.com/newvegas/mods/44515

Purpose: Improves weapon modding GUI, allows you to take off weapon mods.

Load The Weapon Mod Menu after VUI+.

https://www.nexusmods.com/newvegas/mods/59638

Purpose: Fixes annoyances with crafting menus.

https://www.nexusmods.com/newvegas/mods/50480

Purpose: Lets you disable/configure many features of the Stealth suit Mk II.

https://www.nexusmods.com/newvegas/mods/49785

Purpose: Lets you use the Big Mountain Transportalponder! without dismissing companions first and makes you return to where you used it and not the Drive-In. This makes the Sink IMMENSELY more compelling as player housing.

https://www.nexusmods.com/newvegas/mods/50611

Purpose: Turns the Stealth suit Mk II into light armor, making it more useful for sneaking.

https://www.nexusmods.com/newvegas/mods/41865

Purpose: Lets you turn the Sunset Sarsaparilla deputy badges into a wearable item using crafting.

https://www.nexusmods.com/newvegas/mods/56059

Purpose: Makes the Pimp-Boy 3 Billion less bright than the sun.

bCompareArmorStats = 1
Shows + and - on armor DT/DR compared to equipped armor

bDisableHolsteredWeaponFOVZoom = 1
Disables weapon zooming when aiming with a holstered weapon

bAllowFiringWhileLanding = 1
Allows firing your weapon while lower body animations are playing.

bSpinWeaponsSoundFix = 1
Fixes a bug for attack loop weapons.

b24HourSleepWaitClock = 1
Changes sleep/wait clock to display military time. (16:59, for example)

bAddInventoryDropItemHotkey = 1
Adds hotkey Q for dropping currently selected item in Pip-Boy menu.

bAdjustableScopeZoom = 1
Allows scrollwheel to zoom while using a scope.

bAllowActivateWhileAnimPlays = 1
Allows use of the E key (Use/Activate) while performing another action.

bBetterAutoWalk = 1
Moving left/right no longer cancels auto-walk.

bCompanionPipColorChange = 1
Companions now show as white markers on the compass.

bCompareWeaponStats = 1
Shows +/- on weapon DPS/DAM in the inventory compared to currently equipped weapon.

bCompassNPCHeightIndicator = 1
bCompassQuestHeightIndicator = 1
Compass now shows whether NPCs/quest markers are above/below the player.

bContainerRespawnsMessage = 1
Adds warning if the opened container is set to respawn aka unsafe.

bDecreasedDialogueClickDelay = 1
Halves the delay before allowing clicking in the dialogue menu.

bDelayPostCombatLevelUp = 1
Adds a 3 second delay after combat before the level-up menu will show.

bDescriptiveMarkerAddedMessage = 1
Adds the marker location name to the "Marker Added" notification.

bDeselectQuests = 1
Allows de-selecting the active quest in the Pip-Boy Quests tab.

bEquipBrokenItems = 1
Lets you equip broken items (useful for using Weapon Repair Kits).

bFasterSleepWait = 1
Speeds up the countdown when waiting/sleeping.

bFasterTitleMenu = 1
Makes the main menu faster.

bFixDisintegrationsStat = 1
Fixes a bug that inflates your "Disintegrations" stat.

bFixEnhancedCameraGroundSinkBug = 1
Fixes a bug in the Enhanced Camera mod.

bFixItemModMenuUnequip = 1
Fixes a bug that can cause your item to be unequipped in the mod menu.

bFixPerkMenu = 1
Improves the perk selection menu.

bHideGrenadeIndicatorForNoDamageExplosions = 1
Hides grenade indicator for explosions that do no damage.

bIndividialItemStats = 1
Show weight and value for an individual item when viewing stacks of items.

bInstantContinueButton = 1
Skip "Continue from your last saved game?" in the main menu.

bJumpingDoesntDropGrabbedItem = 1
Jumping no longer causes you to drop your grabbed item.

bKeepPipboyLightOnCellChange = 1
Doesn't automatically turn off your Pip-Boy light when leaving an interior.

bLeftAndRightCancelEachOther = 1
Makes left/right movement keys cancel each other when both are held.

bLockNeedsKeyShowName = 1
Adds the name of the key (if there is one) to the "This lock requires a key to open" message.

bNoFoodWornOffMessage = 1
Prevents "worn off" message for food items.

bNoHackingRetryDelay = 1
Removes delay between hacking attempts.

bNoPipboyOnAltTab = 1
Prevents opening the Pip-Boy when alt+tabbing.

bNoSkillBooksAbove100 = 1
Prevents consumption of skill books when the skill level is at 100.

bNoStartMenuDLCPopup = 1
Removes "Loading extra content..." from main menu.

bNoXPBarInCombat = 1
Delays XP popups until combat is over.

bNumberedDialogHotkeys = 1
Adds hotkeys 0-9 to select options in the dialogue menu.

bPatchUnseenCellName = 1
bPatchRespawnedCellName = 1
Adds * to names of unvisited locations, adds + to the names of respawned locations.

bPickLocksEvenWithKey = 1
Holding the shift key allows you to pick a lock even when you have the key.

bPopupMenusDontMoveCursor = 1
Stops popup menus moving the mouse to the center of the screen.

bQuestTextVisibleWhileAiming = 1
Don't hide "quest/location added" text when aiming.

bRapidReloadFix = 1
Fixes engine bug with reload and holder speed.

bRememberAmmoType = 1
Remembers selected ammo type when loading a save.

bRemoveChemWarnOffIMOD = 1
Removes "chem wore off" screen effect.

bRemoveDownloadsButton = 1
Removes "Downloads" button from main menu.

bScopeVisibleAPHP = 1
Makes AP/HP bars visible when scoped.

bShowWeaponAmmoUseInMenus = 1
Shows amount of ammo a weapon uses per shot in the inventory.

bSkipIntroVideo = 1
Skips game intro video.

bSkipSkillMenuIfNoPointsToAssign = 1
Skips skill point screen if you have no points to assign.

bSwapKeyboardYZKeys = 1
Swaps Y and Z keys. Relevant for me because I use QWERTZ.

bTalkWhileSneakingIfShiftIsHeld = 1
When sneaking, holding shift allows talking to a person.

iOpenMapKey = 50
Adds key M to open Pip-Boy map.

bRememberBobbyPinHealth = 1
Remembers bobby pin health between locks and saves. Makes it very tense when you're in Dead Money with nothing but 1 bobby pin.
bHideUnknownNPCNames = 1
NPC names are now hidden unless you've spoken to them.
bHideInvisibleUndiscoveredLocations = 1
The compass no longer shows unvisited locations unless they are marked on the map.

bImprovedHacking = 1
Improves hacking minigame.
bNoAllowRepeatWords = 1
Prevents you from wasting an attempt when clicking the same word twice.
bNoSingleCharacterAttempts = 1
Prevents you from wasting an attempt when clicking a single character.
bRemoveDudIfAllowanceFull = 1
Removes a dud instead of replenishing allowance if allowance is full.
bPowerArmorScalesFallDamage = 1
Wearing power armor scales fall damage.
bSneakAttackWithoutCrouching = 1
Allows you to get sneak attack criticals on enemies even without sneaking, as long as they are unaware.
bWeightlessWornArmor = 1
Makes armor weightless when worn.
bWeightlessWornPowerArmor = 1
Makes power armor weightless when worn.
fCraftedItemHealthPct = 100
Crafted items now have 100% condition instead of 80%.
bShowNameOnDeadNPCs = 1
Shows names on dead NPCs even if they haven't spoken to the player.

https://www.nexusmods.com/newvegas/mods/42926 (use version 1.0)

Purpose: Allows you to essentially hotkey Implant GRX by means of an inventory item that you can hotkey.

https://www.nexusmods.com/newvegas/mods/40807

Purpose: Allows you to move/hold gold bars like most other world objects. My reason for using it is to use gold bars for decoration but because this is an obvious "helper" in the Sierra Madre vault, it's in this section.

https://www.nexusmods.com/newvegas/mods/44569

Purpose: Vendors now restock daily.

If you're like me and get bad RNG at Nellis so your only non-lethal option of obtaining the Boomers hat is the Munitions Manager... Also tremendously useful for "trade route" shenanigans with weapon repair kits.

https://www.nexusmods.com/newvegas/mods/37237

Purpose: Reduces ammo consumption of Gauss Rifles. Separate files for Gauss Rifle and YCS/186.

The one for the Gauss Rifle changes its name to be in German for some reason so feel free to suggest a better alternative in the comments.

https://www.nexusmods.com/newvegas/mods/41853

Purpose: Prevents weapon/armor degradation from regular use.

Warning: This comes with multiple plugins, you wanna disable all but one of them (NRN.esp for no degradation, LRN.esp for mild degradation)

https://www.nexusmods.com/newvegas/mods/66726 (install together wtih YUP patch)

Lets the game continue after the ending slides and the game world will be altered depending on what happened.

Note that I don't recommend using this mod when playing the game in a language other than English because this will add English options in some dialogue menus even when your game is set in a different language.