Vampire necromancers have actually got a nice thing going... They can suck all the blood (and meat, and tissue, and cartilage, and organs, and...) out of a corpse so you're left with a skeleton. You can then raise that skeleton as a loyal follower with one of your first-level baby spells. And the hunger doesn't mean a whole lot, since you just ate.
But it can be a pain to get poisoned as a vampire... That's how my first vampire character died. I just can't keep my hands away from that wonderful regeneration.
Ghouls are great fun though. Munching everything that passes your way, holding onto meat until it takes on that tangy flavor of decay... Mmm...
Not a good choice for the religious types, since you'll have to decide which corpses to eat and which ones to sacrifice.
And yes, I have been sacrificing everything that moves. Hell, I've even been praying before entering battle just in case that somehow gives me more favor for killing enemies while under the effect.
I've been thinking about mummies... I've always found Egyptian-themed stuff to be cool, but I'm trying to figure out how best to kit one of the band-aid boys. Necromancers seem the most thematic, but religious death knights also seem appropriate.