I will always prefer the books to the films. There are certain things that are explained better (visually) in the movies, sure--well, it is a film--but overall, the books (the original material) is the best. It saddens me, sometimes, when people don't recognize a character by their book's description and instead immediately go for the movie actor. Granted I do have some exceptions (but only because some of these characters were very well cast).
There is just something about following it in the book, than watching it on film. If you allow yourself to become lost in the haze of its words, I feel like you'll become a legitimate part of the world. If you are immersed in the pages, you could hear it all, smell it all, see it all, really.
Not to mention the fact that you get a lot more from the story by reading the books, than the movies (which tend to mutilate a fantastic plot).