I'm just going to toss it out there that I've been using a Windows 7 box with Ceton InfiniTV PCIe cablecard tuner for about 3 months now. While it's not something I would put in my parent's house, a techie shouldn't have a problem using it as their primary DVR/media hub.

I have the main machine with the cablecard hooked directly up to my living room LCD through onboard HDMI (Intel HD graphics). My bedroom uses an Xbox360 to stream from the main computer. It has the ability to watch live tv, watch recorded TV, schedule recordings, and almost anything else you could do from the main box.

This setup replaced a Moxi 3-tuner DVR with one Mate. It's a big upgrade from that.