The Road by Cormac McCarthy

I've read every one of his books and this is not only my favorite, but also, the only one of his books that has even the smallest shred of optimism. The movie is also excellent, the filmed it in as many naturally apocalyptic-y places as possible, including Conneaut Lake Park in Pennsylvania (after the ballroom burned), Katrina ravaged New Orleans, the abandoned turnpike tunnel in Pennsylvania, and Mt. St. Helens. But nothing beats the book, where McCarthy is at the height of his linguistic powers.