The Strain, The Fall, and The Night Eternal.
I like good vampire fiction, but I don't read much of it. Before this series my favorite vamp novel was King's Salem's Lot. This is up there and at least neck and neck with it.
I picked up this series purely based on Mr. Del Toro's upcoming film, Pacific Rim.
The first two books are solid and move very fast. A nice mixture of a good virus book with vampires thrown in. What's interesting is seeing a vampire who IS trying to take over the world.
The second book's big reveal was something I'd seen coming, but it was still very interesting and added new depth to the character it's connected too.
The third book was slower...darker. I'm sure that was the intent, but it was almost a chore to get through. It was nice seeing the full story of the vampiric Master and it's end was shocking and emotional. In fact, it's ending is what saved the book for me.
I recommend all three books and am glad I read them.