With the launch of Windows 8 in the autumn I believe that the Zune name is going to disappear and a new Xbox Music service will take its place to improve Microsoft's chances of competing against iTunes and Spotify, the current market leaders. Its a good strategy - for most people Zune evokes only memories of the failed music player (if it evokes anything at all) whereas Xbox is one of Microsoft's big successes.
There is one area where the Zune music service fails: social interaction. Microsoft needs to address this as part of the migration, adding the ability to easily share playlists with fellow subscribers, ensure that playcounts are properly maintained both within the service and in the desktop client; and allow users to post information about their music listening to different social estates: Live, Facebook, Twitter, etc.
Its a small change, but its promotional value for the service can't be understated.