Thanks for the quick answers guys.
I am watching videos about installing XBMC on an Apple TV and this all seems like a veritable NIGHTMARE, and this is coming from someone who actually has enough knowledge and experience to be able to understand everything.
Basically what I want to do is be able to watch stuff I have on my NAS (Synology DS411+) which is in all kinds of different formats (avi, mkv, vob etc.) on my TV, but also have the option to get streaming content from both US and Canada (US Netflix and Canadian sports mostly, although the sports isn't too much of a concern since the ATV supports NHL Gamecentre, and I am already a subscriber). I like the Usenet suggestion for downloads of TV shows though.
Also, apparently the Apple TV can't do 1080p? So I guess my bluray rips would be no good?