For some reason, Ryan Adams's "Gold" has helped me focus for years: http://www.amazon.com/Gold-Ryan-Adams/dp/B00005QY5Y<p>I'm also experimenting with the "soothing" tag station on last.fm. Through that I discovered the "Violet Indiana" artist station as well.
three personal (primarily instrumental) favorites:<p>explosions in the sky: <a href="http://gorankem.com/artists/64517-Explosions-in-the-Sky" rel="nofollow">http://gorankem.com/artists/64517-Explosions-in-the-Sky</a><p>sigur ros: <a href="http://gorankem.com/artists/11546-Sigur-R-s" rel="nofollow">http://gorankem.com/artists/11546-Sigur-R-s</a><p>mogwai: <a href="http://gorankem.com/artists/3544-Mogwai" rel="nofollow">http://gorankem.com/artists/3544-Mogwai</a>
Weirdly, hard trance that I know well. I can work to rock or classic, but something like a good Astrix album really gets me working well. If I know the album well I don't think about it, I can focus on the work at hand.