But the Apple TV doesn't have a display, so you'd need to switch on your TV, select what you want to play, then switch off your TV. If they were serious about music it would have a built-in display - like many competing products.Why would you want to play music through my TV?[/B]
You don't, you want to be able to play it through a nice receiver and speaker set.
Even a bottom of the barrel home theater/speaker set-up will sound better than your computer speakers. How do me and my friends cook in the kitchen while listening to a podcast from the living room if my computer is upstairs in my office? How do I play music at a party from my computer (even if its downstairs, it can't crank enough decibels)? etc. etc. etc. Centralized access to all your media is the name of the game. Even if you don't have a nice receiver/speaker set, having the option of playing music from your living room has several advantages "Hey, I got this great new CD. Want to hear it? Great, lets all go upstairs and huddle in my office" vs. just fire it up on your couch.
Sorry, but its no use for movies (lack of codec support, low res and lack of proper 5.1 sound), and no good for music (lack of navigation without TV being on). I'll pass on this...