I have 3 HTPCs in my house. Bedroom just for music (for now) on a 15" LCD, game room for DVDs, music, and SageTV PVR on a 42" plasma, home theater room for DVDs, games, music, and a remote client for SageTV on a DLP projector.
I actually couldn't be happier with SageTV. It just works - I haven't been on their site for months because it's so flawless for me, though I was thinking the other day I should check for updates. I have a 250GB media drive just for the MPG files. I use 3 Happauge PVR-250s in the PC so I can watch/record 3 channels at once.
Ask if you have any other questions.