I’ve tried the Xbox Media Center, I’ve tried hooking up a full PC to my TV, but nothing beats the tiny little Popcorn Hour A-100 I just received. It’s silent, only wants 12V of power, has a BitTorrent downloader built-in and can access an internal hard drive if you mount one. It plays Full HD 1080p video smooth as butter in XviD, H.264 (even in Matroska containers), WMV — whatever you toss at it. And it costs less than USD 200.
I have no computer that is fast enough to play 1080p video properly when it’s high-bitrate H.264, but this thing chews through anything without the slightest trouble. It has HDMI, component, composite and S-Video outputs, and you can solder an RGB SCART output to it. You can play data off NFS or SMB shares in your network, off YouTube directly, from Flickr and Picasa and from any attached USB storage device. All my external hard drives are ext3 formatted, and it reads ext3 just fine; it’s the native format of the machine. Hell, it even plays DVD ISO images, with menu support, and you can hook up any external USB DVD drive and use that for DVD playback. Even has an eject button for the external drive.
Perfect media player device for the GNU/Linux user (and extended family)? It’s this.