I want to buy an Apple TV but I'm not really too sure if I need 40GB or 160GB. I do not really have a great idea as to how much of a difference that is. Primarily, I want it in order to play iTunes music on my TV sound system. And then maybe if I get the hang of it, I'll use it to buy/rent movies from iTunes... but at this point in time that is not a huge concern of mine. I thought that Apple TV lets you play media from your Mac, so why does it need storage within itself? Does anyone have a recommendation as to which I should buy?