What is your experience of watching a movie and reading the book upon which it was based? (Or the other way around)

To see Blade Runner and read Do Androids Dream of Electric Sheep? (Philip K. Dick) was a bad experience: loved the movie, didn't like the book.

I enjoyed The Name of the Rose movie (Sean Connery is great there), but I still prefer the Umberto Eco book, there is a lot that is lost.

The Empire of the Sun movie was so close to the J. G. Ballard's book, I had my doubts at the beggining about what was first (the book of course). I liked both.

Normally if I read the book, I don't see the movie because I am always disappointed and the other way around.  I pretty much stick with books though - much better IMO