A couple of years ago we (a few colleagues and me) used to listen to some internet radio (streaming) until we get caught (we used too much bandwith at that time)
We then used an old server to stock 80 GB of MP3s (and some videos too)
Rather than my boss on the phone (conference call) or the latest manager's meeting as background noise I'd rather listening to some good music which doesn't interfer my my concentration