I'm using Spotify, the collection is pretty good and Premium is rather affordable. Their premium bitrate is equivalent to 320, but using some ogg derivative using lower bandwidth. I don't know if it works well with the SB Touch, but you can use it from the web browser, it has apps for mobile devices, and it's possible downloading the files (even at the highest bitrate) to keep them in your device to play when there's no connection. I'm pretty happy with it.