The Sprint Music Store fits the bill if you're looking for instant gratification on the digital music front, but the $2.50-per-track price tag is hard to swallow.
Winamp is still a fun player for customizing your playback experience, but most users will prefer the all-in-one experience of Windows Media Player or iTunes.
Wal-Mart's Music Downloads is the cheapest place for Windows users to purchase tunes online; just be prepared to find mostly mainstream music.
Despite some glitches, MTV Urge is one of the best subscription music services we've seen to date. If taking your choice of millions of songs with you anywhere sounds appealing, make sure you check out this offering from MTV.
The intuitive and aesthetically pleasing Zune Marketplace works well as an audio jukebox and Zune companion, but it's missing some key ingredients that would make it a one-stop shop.