What is the name of the song played on the "Halo" video game commercial?

It is a haunting solo piano piece with lots of minor chords. I really love it and want to know who composed it.

Lithium09xox2007-10-19T16:42:53Z

Favorite Answer

the name of the song is "Raindrop" by Chopin. I looked 4 it on iTunes but i couldnt find it but i did find this...
http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewAlbum?playlistId=4146176&s=143441&i=4146171

and then the song is here 2...
http://www.youtube.com/watch?v=vjhSp7xGsMc