Last.fm is such a great Musik site. After creating your own account, Last.fm listens to what Musik Du listen to and eventually plays your field of Musik and nothing else ;)
Last.fm is the best site. Du can listen to music, discover artists, chat to people, plus it generates your oben, nach oben listened songs and artists. The most fun bit though is Du can compare your Musik taste with other users, and make Friends oder whatever :)