This was an easy one, as I'd stepped out on a limb just recently. Written in Red had sounded like a good book but I'm not a huge reader in its genre and was pretty sure it wouldn't be my favorite.
Boy was I wrong!
I devoured this book and immediately went to checkout the next book that had just come out. I'm now waiting anxiously for the next one...and think I'll probably read these two books again before the year is out!
Another choice, which I talked about just yesterday, would be Harry Potter. Another series of books that won me over despite myself.