I definitely love vampires–love their strength and the fact that they aren’t good. There is always some bad in a vampire–something that probably comes from their need to feed.
I think you could probably extend this out to encompass all creatures of the dark–demons, werewolves, the whole lot of them. They all harbor their secrets and their sense of self hatred that makes them the flawed and brooding heroes we have come to know and love.
Throw into that mix a vampire hunter or a woman who doesn’t know what she’s in for and you’ve got a great story on your hands.