[gregcain]

I'm using a Mac Mini as a front end to my BeyondTV, and it works great. The only real catch is that you have to record everything into H.264 using the optional ($) plugin, and then mount that drive onto the Mini.

I can't think of any reason this wouldn't work for the AppleTV with a little bit of hacking.

I set up my TV with a Logitech remote - two simple buttons to switch between TV and the Mini. My wife loves it.