Seeqpod is actually a cool idea. A robot like thing is slowly indexing every publicly accessible mp3 on the intertron. There has very rarely been a song that i couldn't find on there. Streaming only, but you could prolly use this to find mp3's for free. Can also crate playlists to send to people. here is a sample playlist of some of the good songs from rolling stones best 100 songs of 2007 list.
iMeem is what myspace wishes it was instead of an assault on my eyes and ears. like youtube for audio and it has the blessing of the labels. I like the playlist creation here as its easier to send to people.
found this one the other day. like digg for musicians. musicians send up mp3s. people vote on it. had me hooked when the first time i loaded the site up radiohead, iron and wine, girl talk, and m.i.a. were all on the front page. not sure if its going to have legs, but it has a nice interface. In fact, you can click around the site without the current song stopping, which i dig as a complete dork.
i dont know anything about music sites. the only site i visit on the internet that has anything to do with music is pitchfork and 80% of that i dont follow. the kid next to me uses pandora. maybe ill mess with this stuff today since i have lost all ability to be productive in light of the impending holidays.