I'm not sure why you need to haul your Apple TV around (though it might work if you spend a lot of time in hotels, or traveling between two houses, which is certainly a possibility), but if you do find yourself moving Apple's set-top box often, you might as well do it in style, right? For that reason, there's this custom-fitted WaterField case, which has everything you need to move the new Apple TV from place to place, and look really good while doing it. It's $45, which isn't all that cheap, but if you've ever used a WaterField case, you know it's probably worth the price anyway.
Also in the category of excellent cases for Apple accessories: Tom Bihn has released a case for the Apple Wireless Keyboard. Like most of the Bihn cases, this one's exceptionally well-designed, combining solid protection with pretty excellent style. If you've been hauling around an iPad and a keyboard to use with it and want something that will secure your cargo a little better (not to mention turn heads on the plane when you pull it out to use), you can give that a look. It's available for $30.