In my quest for legal music, I've been doing quite a bit of research. iTunes looks great but has one serious shortfall. When you buy a track, you are locked in. This means that you must use iTunes or an iPod to listen. I've got a mac but I use linux more often so this would be a problem. Another problem with iTMS is that if you lose the files, you are sol. You cannot download them again. This may be true with other stores, too, but I don't know.
Most other stores support only windows (which I don't have at all) so that's even worse.
I looked into Napster and Rhapsody and found a common misconception. These services claim to offer unlimited downloads for $5-20/month. Wow, a helleva deal. Alsmost. That's a subscription fee, meaning that you can only play the music so long as you pay the fee. Thie makes the service more like subscription radio than like digital cd sales. Also, with these services you cannot put tracks onto an ipod (only certain other players). Since I have an ipod that's a problem. And again, no linux support.
I am annoyed that these companies downplay the subscription thing so much--it is very misleading. One particular commerical comes to mind...it pictures a chart that indicates filling an ipod from the itune music store could cost $20,000 while filling a similar player with their service costs only $15 (per month. If you don't pay, you can't play. I can't believe you actually enlarged this to read it, dork.). Sure it'd take you a while to get up to $20k on the monthly plan but still, very misleading.
So, until we have a music store that provides plain old drm-free music files that is compatible with linux, mac, and windows, i'll have to stick to ripping ol' fashioned cd's :)