I've always loved the idea of different "strains" of vampirism, based on different blood-sucking/scavenger animals. Here's a list I made a few years ago:

Bats:
Theme around the classic "brooding noble" vampire. Prideful creatures that prefer their victims to be young and attractive. Picky eaters who only bite the neck.

Rats:
Themed around disease and filth (which they spread). Cowardly creatures that only attack the sick and elderly. Furtive eaters who drain from the wrist.

Fleas:
Themed around hedonism and corrupt aristocracy. Cackling creatures that gather in decadent balls, where they use humans for entertainment. Wasteful eaters who drain from many shallow wounds.

Crows:
Themed around knowledge and sorrow. Insidious creatures that pray on those suffering grief and misery. Sly eaters who will mimic the eating habits of their cousins.

Jackals:
Themed around brutality and bloodshed. Viscous creatures that spread terror before striking. Messy eaters who always consume the heart.

Leeches:
The primordial vampire. Mindless, shrieking things locked away in dark places. They have no preference for who they attack, leave no bodies behind, and are never satiated. The oldest and purest form of vampirism.