For some reason, Ryan Adams's "Gold" has helped me focus for years: http://www.amazon.com/Gold-Ryan-Adams/dp/B00005QY5Y
I'm also experimenting with the "soothing" tag station on last.fm. Through that I discovered the "Violet Indiana" artist station as well.
explosions in the sky: http://gorankem.com/artists/64517-Explosions-in-the-Sky
sigur ros: http://gorankem.com/artists/11546-Sigur-R-s
mogwai: http://gorankem.com/artists/3544-Mogwai