The popcorn Hour you're looking at is possibly the best media player out there in terms of functionality. The Netgear EVA-8000 is also pretty good and a heck of a lot cheaper.
I personally use a self built HTPC for all my needs, along with my PS3 and the PS3 Media Server sotfware which allows playback of pretty much anything on the PS3.
I'm also considering an Acer Revo for the bedroom for playback. At £150 it will playback all my media from the HTPC at a low cost and its tiny.
http://www.play.com/PC/PCs/4-/960679...C/Product.html