Life Hacker has a new post up evaluating the 3 major music services: iTunes, Google Music, and Amazon Mp3. In addition to a straightforward evaluation of each service, looking at the pros and cons of each, it goes a little deeper and talks about WHO will get the most out of each service, recognizing that people with different needs, likes, and personalities will prefer one service over another. They also touch very briefly on some of the smaller services and streaming music services that are out there.
As always, be sure to also read the comments section. One reader posted about a site called Beatport, which I was unfamiliar with, for listeners of electronic music, trance, house and (*shudder*) dubstep.