When films are adapted from books, more often than not, I tend to find the books a lot more enjoyable. So I have skipped watching a lot of films in the hope of reading the books later.
So what are some great films not adapted from books? Or what are some films that are significantly better than the book they were adapted from?
2001 Space Odyssey might be an interesting candidate here, just because of the way in which the book and film were more or less born together and diverged in their own separate ways, though the genesis of the whole thing was apparently in a short story by AC Clark that I know nothing about.