Um, none? I feel that most books would do better being turned into TV shows (AGOT and True Blood season 1 come to mind) because it allows for more long-form storytelling.
But if I have to choose the least disappointing one, I'll go with The Hunger Games. The book was written like it was a movie anyways, so it didn't really lose too much in the translation from book to screen.
Y'all thought I would put the PTerry movies didn't you? NOPE - they are good, but not nearly as good as the books. Because nothing's as good as PTerry is.