The score to the Lord of the Rings films, hands down. Howard Shore did a hell of a job, the music was just superb and epic.
Requiem For A Dream ( darren Aranofsky ) takes the cake. I think it may be one solid piece but I never did the research. Its the best soundstrack without songs that people recognize and it definitely makes the movie one of the top ten ever. Trainspotting is good for older drug pop.