I think the title should speak for itself, no? It doesn't have to be the 'soundtrack' that actually got released on CD, as some/most times they only feature the more well known songs and leave out the instrumental stuff, also discuss favourite composers and such.

The one that pops into my head straight away is Almost Famous, not only does it have some wicked songs, but the music that was composed specifically for the movie is beautiful as well. I also love most everything I've heard of Clint Mansell's.

No doubt I'll think of more.