been looking at apple TV too... just wondering if I could combine it with my Time Machine as a kind of music storage jobbie
As long as you use a computer to access media on your TC via iTunes, you can stream it to your ATV2 (which recognizes your computer running iTunes Home Share).
Therefore if iTunes can play it on your Mac, ATV2 can stream it to your TV so basically it's possible but it needs to run through your computer.
I think the only way of doing it without the computer is a NAS drive
I could be wrong 
thats fairly pants 
still... it can play sh!t directly from the iphone so all is ok 
Indeed from your iphone or ipad via airplay & mirroring

i tend to play my music on my computer then stream it to both my atv's in different rooms as you can control everything from your phone like independent volume on each atv access to all your playlist etc etc via an app called Remote.
For £85-99 they are a cheap solution but defo improved by jailbraking (
http://support.firecore.com/entries/387605 & load on atv flash from
http://firecore.com/atvflash-black which makes loading software onto it childs play) but if you don't want to jailbreak them for films then just use Handbrake to convert your films to mp4

i do convert some films to mp4 for watching on my ipad as you don't get the letter box effect after converting just lose a little off the sides