I don't buy to many movie soundtracks but here are a two of my fav's.
Reservoir Dogs (listing to it right now, the movie is awsome and the soundtrack is just as good. Cool 70's stlye music, nice to kick back on the deck and open some vino.)
Singles soundtrack (The movie sucks but the soundtrack is great. If your a fan of the early seattle alternative sound this is a must have.)
What else is good?