Generally speaking, I find movies disappointing after reading the book. I am looking forward to 'We were Soldiers" though. Topical, because it is released today. I'm not a big Mel Gibson fan, but the Authors of the book on which it is based "We were soldiers once, and young" (Hal Moore and Joe Galloway) both agree it is a great depiction.
All the Pretty Horses was a great adaptation as well. I thought that The Rainmaker was by far the best movie out of all the Grishams. Not that hard, mind you, but it was still an outstanding movie.