I'm looking around for similar devices right now. I've also got friends and family that are into it.
One friend has a Boxee install going on Windows 7 w/ HDMI output to his TV. He's also got a device that streams over the air TV signals through his network which Windows Media Center picks up and he uses that as a DVR. Then he's got a custom remote (like $150) that drives everything. It's pretty slick but he's got darned near $1k into it all I think.
My brother grabbed a D-Link Boxee Box (which runs Linux) for about $200 a while ago. It works, I guess, but it doesn't have Netflix streaming yet and it was supposed to ship with that. My brother is not happy with it.
I'm starting to lean toward getting a Blu-Ray player that'll do NetFlix, Hulu, and play media files off network attached storage. I figure I'm going to have to get a Blu-Ray player eventually, and it'll have to have a network connection anyway, so if I can get one device to do it all that's probably best. I'm seeing one from Toshiba out there that's only $110 or so and does everything except play off network storage. I'd have to manually download videos to an SD card for it to play them. Workable.