The main thing that frustrates me with using AppleTV to stream from iTunes is that if I am playing an internet radio station, like Radio Paradise, that pushes track info out as part of its stream, the AppleTV screen does not show this information. So I have to go to my Mac in another room to find out what great track it is that is playing, which should be unnecessary. I take the point about every application being different, but surely a special-case for iTunes would be worthwhile? Apart from anything else, it would add value to using Airfoil to stream from iTunes rather than simply using the built-in AirTunes functionality, which doesn't provide track data from internet radio streams.

Incidentally I believe this is because Apple is not keen on people using AppleTV for internet radio because it is a way of getting unlimited content for free. Otherwise I can't really understand why they haven't supported internet radio better, or better still implemented the Internet Radio tuner feature from iTunes on AppleTV. Personally I think this is a shame, as additional functionality of this type would surely help to sell AppleTV, and most people listen to radio when they are doing something else so not in a position to watch purchasable video anyway. /rant