I was reading a good book series called Cirque Du Freak about a year ago. Its by Darren Shan and its about a boy who ends up becoming a vampire. The book goes into detail about vampires and the myths and stuff behind them. Its a fantasy book definitely but it has some action scenes thrown in and mixes the horror in at the right times too. Its about 12 or 13 books long and even though it starts out slow by the 3rd book your already deep into the world of vampires. By the end of the series you start thinking so much that by the time your done with the last book you have no idea what just happened.
I would highly recommend it to anyone who likes fantasy/action/horror thrown in with a little vampire mythology.