Matthew (A Discovery of Witches, All Souls #1, by Deborah Harkness)Read about another entry on the list.
Where vampires go, there must also be witches. Diana Bishop is descended from a long line of powerful witches, but wants nothing to do with magic. But then she summons an ancient text, and along with it, her destiny—and her love, Matthew, a vampire geneticist (a smart nerd/sexy vampire? Who could ask for anything more?). Future books involve time-travel, adventure, and of course, a hell of a lot of romance.
Also see Lauren Owen's top ten vampire books, the ten best vampire novels ever, the top ten vampires in fiction and popular culture, ten vampire stories more romantic than "Twilight", Kevin Jackson's top 10 vampire novels, and Lisa Tuttle's critic's chart of top vampire books.