I've been listening to EpsilonLab's network albums for the past three days at work, and I must say I've really enjoyed what I've heard so far. Lots of background music, but also a few pieces that made me sit up and listen all the more. (And there were a few pieces that took everything I had not to hit the "next" button in XMMS). Don't take my word for it, though; go ahead and check 'em out. (They're also available from LegalTorrents).