I also think that the Apple TV could become much more than what it is right now. I actually don't have one because I can't yet justify the price to myself, but traditional cable is not the way I would like to enjoy TV and movies. Hulu and Netflix streaming (and a bit of movies from iTunes) is what I use and I wish the Apple TV was delivering that in a smart way (and without hacking).

I am really looking forward to the day Apple will stop calling the Apple TV a "hobby" and do something cool with it. The App Store (or an App Store) might be the way to go…

As for iTunes, as jkincaid said, the catalog is now DRM-free so it's not as much of a lock-in problem. But right now, there isn't much to move your music to. You can replace it with services like Pandora and Last.fm, but your music library would stay where it is. However the acquisition of Lala.com and the rumors around itunes.com (if they become true) have the potential to maintain Apple's control of the music part when it moves towards a completely streamed system. And in that domain, Apple's mindshare is already so huge that it would assure their success if they execute on time.