I just finished World War Z, and I have to say I am very impressed by Max Brooks. He obviously really thought about the consequences of a zombie infestation and how it would go. But more important, he manages to create characters that you care about. And when the book is over, you have to force yourself to say goodbye to. Some books you can just walk away from, but a good book forces you to say goodbye to it.
I haven't come across many like that. Hyperion was one, and (I'm kinda ashamed to say it) Harry Potter. Night Watch, too, although I'm still waiting for Book Four to get released.