It is common knowledge when it comes to the movie version of books, the book is always better, however in a few cases, the movie is actually pretty good. In no particular order, these are the movies I think fit this criteria:
1. Of Mice and Men (1992) Gary Sinise did a great job converting this novella into a movie. The length of the novella does seem to play a large role because very little had to be cut to fit the length of a standard feature film.
2. The Crucible (1996) Beside the fact that Daniel Day Lewis makes an exceptional John Proctor, this movie is wonderful because Arthur Miller was one of the screen writers. He made sure his work was not butchered by the movie makers. (Trivia: Daniel Day Lewis met Arthur Miller's daughter Rebecca during the filming of the movie and is still married to her.)
3. The Age of Innocence (1993) Again we have an excellent film starring Daniel Day Lewis. While there are of course some differences between the novel and movie, it is generally faithful to the book. Now, you may be noticing an affinity for Daniel Day Lewis and I certainly have that, but on my "Not good movie versions of books" list is Last of the Mohicans (1992). Do not get me wrong, this is a superb movie, but it is not a particularly close interpretation of the book.
4. The Cider House Rules (1999) I guess John Irving learned his lesson after movie makers massacred his book A Prayer for Owen Meany and turned it in to the monstrosity that was Simon Birch because he was involved in writing the screen play, and even played a small role as a train conductor.
Sadly these are all I can come up with...though I must admit there are movies I have seen but not read the book or vice versa so I cannot speak authoritatively. There are also many wonderful movies that happen to be based on books, but are not faithful to the book and therefore not appropriate for inclusion on this list. Maybe I will make a list of those in the future. I would be glad to have input about my choices and additions to the list.
