Downloadable music will also die. Spotify, or equivalent streaming services, have the clear killer feature downloadable music is missing - access to all music on any machine with an internet connection. Carrying around your data will seem antiquated really soon.

Edit: For the US readers I'd like to clarify that I don't count any other existing services as equal to Spotify, but there will surely be copycats soon. It is the iphone of streaming music applications if you like analogies.