It depends on the music store you want to use? If you use iTunes then you have to use an iPod. Also the acc codec that apple uses to encode its music, is superior to mp3 because it is better at comperesing music so you get beter sound quality out of a smaller file, which means more music on your iPod or Computer Hard Drive, btw you don't have to use iTunes if you have got you music "other ways" than you can still use it on your iPod in mp3 or acc codec. Also I have heard that the iPod is tops in sound quality when compared with other mp3 players.