Spotify for iPad has at last been released after much wait. The app actually looks amazing and seems to be a blend of many concepts made by others from all around the net.
It mainly uses album art and layers to overlap and make everything look pretty. You can send and receive songs to friends, make playlists, search songs, find out what's new and if signed into Facebook, can look at what playlists your friends have published.
You can get 48 hours of a premium account for free by signing in with your Facebook account so it's worth trying out.