Mine is jailbroken, I've installed Plex (and mark my words.. XBMC is coming, I can sense it).. so I can stream all my movies from my PC to my AppleTV, even 1080p if I wish.
Not to mention I bought it with full intention of jailbreaking. Currently it's sitting on my desk running Lighttpd + PHP + MySQL, acting as a web server.
It was 100$. I didn't buy it for its media possibilities, I bought it as it's an iOS device, so inevitably the Jailbreakers will have their way with it, and make it do something cool.
Netflix streaming (cheap, small and silent.. definitely a plus to running a PS3 or Xbox for Netflix). iTunes Store is pretty useful for movies.. basically instant playing.
It's definitely still Apple's "Hobby".. but it exploits the fact that it has iTunes Store to its maximum potential.
Not to mention the USB port is meant as a diagnostic port (EG: Restoring iOS firmware).. The Apple TV acts as a device, not a host.