I haven't scoured this thread so I may be repeating other people. But, O Brother, Where Art Thou? has an awesome soundtrack. also, and in a much different way.... Tron: Legacy has some wonderful tunes.
It's so hard to decide because they do say that the music makes up 60% of a scene, without score and soundtracks it's difficult to imagine what iconic movie scenes would be like without that audio signal that increases tension or comedy or action.
Muir Races to Work - Harry Gregson-Williams : Spy Game (2001).
The Prophet - X-Ray Dog : Un jour sur Terre (BBC's French version of 'Home' (documentary).
All Devdas (2002) tracklist.
Ghost in the shell (1995) - Kenji Kawai
Red Warrior - Hans Zimmer : The Last Samurai (2003)