For edgy iPod owners everywhere.
GarageBand.com (not affiliated with the Apple software product) offers a mechanism to find new music that suits your taste. The Gpal companion for iPod and iTunes is in free beta trial. It will create and maintain your playlists automatically. It will even match your musical tastes to new music and let you play it from your playlist without you ever owning the song.
I might have to give up and get an iPod….