I always thought of vampires, especially the young-adult ones, as a metaphor for sex - sucking blood, forbidden, taboo. I think they just ooze sex. Vampires are all the big themes in life in one attractive, bloodsucking package.
“It didn't matter what you look like. You don't have to get up at 5:30 in the morning and there's a lot to be said for that. Corpse Bride can just play all my parts from now on and I'll just do the voice.”