Currently for me it's the Assassin's Creed II soundtrack, although that's getting pretty old quickly. I almost always listen to music while working. It gives the unconscious portion of my brain something to process and if it's a soundtrack it makes my work feel 3x as important.
Then again, it can be distracting sometimes, especially when trying to read something like an article. So, do you listen to any music while working, or do you prefer to keep it quiet?
Spotify is a godsend for stuff like this. I can just hit up any album I feel like and let it stream. Only downside is those annoyingly loud advertisements.