Jaws remains, to this day, one of the few horror movies I can watch and that I can watch over and over and over again. Of course, every time it comes on and I'm watching it with my mother:
"He and Brody's wife have an affair." and "He dies." (Said of Hooper.) My mother read the book as well as saw the movie. Obviously, they left stuff out.
Also, I love this, too, if you don't mind a plug for youtube fave:
http://www.youtube.com/watch?v=hZgMJ-WFzPg (Num num num)