I don't have a favorite book, but I really enjoyed the Harry Potter series.. the Inheritance Cycle kept me satiated for a bit after finishing Harry Potter, but Poalini used too much of his inspiration in writing names of places/parts of the story.
I've read several of Dean Koontz as well, and the one I liked the most was The Good Guy.. haven't read one of his in a while though.
I've been looking for another fantasy to read, but none interest me anymore and I almost always leave a bookstore empty-handed. I have started writing the basics of my own fantasy though, and I'm building it from stories I'm writing per the advice of a book I recently bought.. I have one story written and am working on another one now so I'm hoping to get somewhere with it.