In reply to ksjs:
The music in the clip is almost certainly being performed by The Hilliard Ensemble. It's pretty hard to miss their distinctive sound.
The recording style is also very distinctly that of the german ECM record label.
So, start here :
http://tinyurl.com/2xdw85
The Amazon site has music samples to play.
I would particularly recommend their performances of the music of contemporary Estonian composer Arvo Pärt.
If you don't know these works, prepare to have your socks blown off..
Cosmic John.