This is the cheapest (and only) current ATSC/QAM tuner available (AFAIK); http://epvision.com/ They will have a new version by the end of the year available with a NTSC tuner. Current model doesn't have one.
I was looking for the same thing. They don't make them yet, but I guess this spring they will start as it will have to be a digital tuner. You can either get a HD DVR or just settle with SD on a DVD recorder. I opted for a toshiba d-r5 with a SD tuner and then planning on getting a HD DVR box from my cable company next spring.
This is probably not exactly what you're looking for, but I've been recording ATSC HDTV onto my computer since 2004.
I then use NERO software (version 6) to convert to DVD (720X480) and burn a regular DVD that plays on any set-top DVD player- the results are as good as the best 720x480 content coming out of a studio.
The final disc is not HD, but it's been a great interim solution for me until HD disc burners become comonplace.
Here's the ATSC capture card I have in my PC - this card is very, very reliable in my experience and I think you can find on-line for about $130, maybe less.
I picked up Sony DHG-HDD500 60-Hour High-Definition Digital Video Recorder (500 GB) over a year ago and I absolutely loving it. The picture is just breath taking. It comes with HD tuner built-in with TV guide on screen programming. I mainly use it for recording off the air channels. It doesn't have A/V input which I don't really need. It comes with HDMI output with dolby digital 5.1
I subscribe to regular cable and this receiver picked up all the HD local channel like ABC, CBS, NBC, Fox, CW and PBS. I don't even have to put the antenna up.
If you can get a hand on it, get one. It's a little bit pricy but it's worth every pennie of it trust me.