I don't mind vampires when they're done properly, and - with the exception of the weird "vampire face" thing - they're done very well in Buffy.

Plus, it's not like every episode is about vampires. It's kind of like The X Files - you'll have your "mythology" (in this case, vampire) episodes, but in between you have a lot of "monster-of-the-week" episodes.

The Halloween costume episode I mentioned was about a costume shop that sells Halloween costumes that literally turn you into whatever costume you're wearing. Another episode was about a cursed Incan mummy returning to life and sucking the life out of people. Another was about a kid Frankensteining his dead brother back to life, then Frankensteining an undead woman for him to live with.

So it's not solely about vampires.

(this is the main reason I hate 'twilight' - it's pretty much ruined vampires forever for a lot of people)