I think that, ironically, Amazon and Google's push into cloud based music will play to Apple's advantage. The music labels will want to get in the game, and Apple is now their best choice since it would send the wrong message to launch with Amazon or Google now. As a result, Apple will get a better service (one that doesn't require you to upload all your music and requires much less server space). I'm trying to sign up for the Google music service, but I hope Apple comes out with something soon that integrates with iTunes and doesn't require me to waste time uploading 20,000 songs.
That's perfect for those with iTunes-only content. What about the rest of us with huge, diverse music collections that really just want a digital locker? I don't want the labels interfering with MY collection.