We can get something called Hauppage here in the UK - the PVR is pretty good.
Im sure you can get something similar in the US.
All the mpeg2 encoding is done on the card so there is zero degredation on your PC.
They have analogue, freeviewdigital and satallite systems.
have a look at
http://www.hauppage.co.uk and look for a US version.
edit: lol - guess what? it is
http://www.hauppauge.com