One suggestion is to make it easier to look up the artists/songs that you enjoy. I find it hard to select the text of the artist/song because the anchor tag fills the entire width of the screen. Perhaps a nice way to approach it might be a "Info" link somewhere, maybe just when the song is playing, which just sends the query to Google or something.
Later on, you could hook it up to some other sort of service which provides better info.
It would be neat if there were a way to save songs for later consumption. As a spotify user, I would love to be able to "star" it so it saves to my account, but I'm not sure if that is possible on the web