I'll be honest i was tempted to say the only decent vampire movie is Dracula: Dead and Loving it starring leslie nielson
c'ptain... the retard-o-tron! she cannie take no more!
You might be tempted to say you have taste, but I hope your other senses counteract this urge :p
On a serious note I'm guessing you've seen none. You should try Near Dark, its a more serious take on something people attribute to Fright Night (post modern vampires?
). I also like the Fearless Vampire Killers which is a nice Polanski movie, can't wait for a HD release of that! Lifeforce is about vampirism, as is Rabid. From Dusk Till Dawn is a classic.
There's 5 or 6 others i've not yet watched that are supposed to be good too, but i've not seen em yet so won't mention them.