So many excellent soundtracks here! I second friend Toast's nomination of The Motorcycle Diaries also by Gustavo Santaolalia. One time I renamed the songs from scenes from Brokeback Mountain, and now they have become a second soundtrack on my ipod!!
New soundtracks I love are the ones from Slumdog Millionaire and 127 Hours, both by A.R. Rahman. They also have good music to work out to!