A beautiful Masterpiece like the movie, the Serenity Soundtrack is a outstanding piece of scores and originality in the use of instruments. I've never heard anything quite like it before.
On this page this a little sample of the tracks, only parts of it but it gives you the feel, if you go to the track called 'River and Simon in locker' you'll get what i mean.
http://www.soundtrack.net/albums/database/?id=3888 