Monday should bring the much anticipated dashboard update that will allow background downloading of Marketplace content. So while waiting for the latest video or demo to download there will be no need to star at a progress bar anymore. My personal favourite improvement however is persistent music, so if you are playing an album in visualisation mode then choose to play an arcade game, starting the game will not stop the music.
IGN has some Videos of some of the other improvements.
Edit: The update wasn't released on Monday.