Well people here seem to be suggesting FILM SCORES and not so much soundtracks, but seeing as I very much enjoy the particular soundtrack I am about to list, and this was the only general SOUNDTRACK thread I could find, I'm posting anyway!
Danny Boyles' THE BEACH is a movie that gets alot of mixed reactions. I quite enjoy it but I know other Chewers consider it to be a misfire (I am one of those who likes SUNSHINE too, to give my BEACH appreciation some context)
What I think is beyond dispute though is that it's soundtrack is by far one of the best SOUNDTRACKS of the modern age (top 100, easily - IMHO)

Favorite tracks of mine include such hits as....
Snakeblood - Leftfield!
Pure Shores - All Saints!
Porcelain - Moby!
Spinning Away - Sugar Ray!
PS While we're on the subject of filmscores though, I want to give a shout out to the score from THE ROAD. The movie is one of my favorites of the past few years, and the opening 16 minutes are about as haunting as anything I've ever seen in film. A stand out track would IMHO be the titular THE ROAD, track #2 on the OST. Give it a listen sometime... it's extremely depressing! (but also hauntingly beautiful)
