Here's the thing. I don't read a lot anymore (not as much as when I had more free time as a student) and when I do, I don't seem to read books that get adapted to film. I've read about 10 books this year and the vast majority have been non fiction and would never be turned into films (maybe they would be documentaries if I stretch my imagination). So I guess I don't have a favorite. This is partly for the above reason and because the book-to-film adaptations I have seen weren't that well done, so at the moment I guess the only thing that might come close to being a favorite is Lord of the Rings.