Musician Nissa Ludwig puts a compelling spin on pay-per-download sites. Her LightningCD site not only lets you buy an album for ten bucks, like iTunes, it automates the process of burning that album to disc and printing official cover art and liner notes.
Ludwig may be a little ahead of the curve here. Until someone can come up with an affordable, standalone unit that pops these things out fully-formed, the way that Kodak and HP have done with photo processing, mainstream users will balk at the cut-and-paste nature of the project.
Still, for only a $39 setup fee, it's a compelling distribution strategy for bands with lots of good tracks but no cash to get into the distro pipeline.