Internet Radio Streaming
In his review of the "Who Owns the Culture?" event, A VC mentioned that the costs of Internet radio are daunting, even for the likes of David Byrne. I have no idea how to fix the copyright fees, but I think a good way to decrease bandwidth costs would be a commercial version of End System Multicast, which distributes content via p2p. The technology is a bit like BitTorrent's, but ESM has additional intelligence to support live streaming. It's an open question whether users would be willing to donate bandwidth, but there's a good chance since the bandwidths are low and people are often passionate about music.
Oddly enough, years ago there was a startup, ChainCast that was trying to do this, but it looks like they've abandoned the p2p approach(also, it looks like they're out of business). Why did they fail? Maybe because they were trying to sell this stuff years ago, way before broadband was widely available. Regardless, I have to believe that p2p streaming is going to happen one day. We just need to find a killer app.