I find these to be a bit of a pick me up when I'm down.
http://www.symphonyofscience.com
"Unbroken Thread"
[youtube:33llqh4q]http://www.youtube.com/watch?v=hOLAGYmUQV0[/youtube:33llqh4q]
"Our Place in the Cosmos"
[youtube:33llqh4q]http://www.youtube.com/watch?v=vioZf4TjoUI[/youtube:33llqh4q]
"We Are All Connected"
[youtube:33llqh4q]http://www.youtube.com/watch?v=XGK84Poeynk[/youtube:33llqh4q]
"Glorious Dawn"
[youtube:33llqh4q]http://www.youtube.com/watch?v=zSgiXGELjbc[/youtube:33llqh4q]
Check out the downloads page for the originals and some remixes.