I looked at this recently, specifically for recording over-the-air (OTA) to avoid the cable bill.
Sezmi looks really promising, but at the moment it’s only available in LA.
”What Sezmi offers is value, convenience, and personalization. For $5 per month (plus $300 for its hardware), you receive an indoor digital antenna (gussied up to look like a speaker) and a 1TB hard drive, capable of holding up to 1400 hours of programming.
“The system receives local digital broadcast channels. And, if you upgrade to the $20 per month package, you also get a group of basic cable channels, transmitted over the unused bandwidth of its local broadcast channel partners.”
HDHomeRun is a network DVR, you have to watch on a PC or hook a PC to your television.
HDHomeRun® Digital TV Tuners
* Watch TV from any computer on your network.
* Record full 1080i broadcast resolution.
* Pause, rewind, fast-forward live TV.
* Schedule and record all your favorite TV shows.
* Expand with multiple HDHomeRun devices.
And there’s the DIY DVR PC. Here’s a thorough guide to building one.
Ars Ultimate Home Theater PC Guide: 1080p HDMI Edition
If money were no object, I’d probably just get cable and use the DVR they give me. I used to have Comcast and their dual-tuner DVR was excellent.