Vampires, if done right can be extremely entertaining.
Take Hellsing for example. Alucard has a great character design, great back story, and while Crispin Freeman has been ho-hum for me for his voice overs he does a great job. I also enjoyed Karin thanks to her being a non-conventional vampire and a nice little love story thrown into the mix.
Toss out a few more vampire anime's and I'd be happy to have a peek.