Any film "soundtrack" which is just a bunch of other peoples song (Pulp Fiction, Trainspotting included!) is just a cop out, lazy.... ;-)
Dirty Harry, still makes me shiver when I watch that film, and I got to go to some of the locations in the film recently!
Bullitt is an awesome soundtrack, great to listen to on its own
Star Wars Trilogy (the proper one), amazingly good to listen to on its own
I used to manage a music shop and I put loads of soundtracks on, some of them are so amazing they sometimes outshine the film itself! Or at least make the film as it does.