I loved the book, but the movie was even better, IMHO. The funny thing about Robin Williams, I like it when he's not trying to be funny. When he is being funny, he's a hoot and a half. It just seems that he never gets due recognition for the serious, though. I'm thinking "What Dreams May Come". I still cry every time I see it.
Another that fits this category,"Anatomy of a Murder". Jimmy Stewart and Lee Remmick. She was the perfect 1950's out-of-her-element hussy in the wilds of the Upper Penninsula of Michigan. Jimmy, the perfect backwater lawyer, ready to be taken in by a pretty face and bullet breasts.
And, of course, "Johnny Got His Gun". The book and the movie were pretty equal. The definitive anti-war movie.