Hairy Minotaur said:Lords of the Night: Vampires - Bottled Imp Games
It just makes vampires nasty and the kind of creature that can take on a party of 6 all by itself.
It's a 3.0 product so you'll have to do some minor tweaking, but well worth it in the end.
Aus_Snow said:If you don't have a problem taking stuff from other systems though, I recommend Blood Types (GURPS).
jaerdaph said:I second that. And, you can the 3.5 edition edition as a PDF here.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.