Background. I have comcast cable in Oregon. I have an old Series 1 tivo. I can watch shows in HD on my 37in Vizio LCD.

I want to get a capture card for my pc that allows me to have a pvr that records HD. (I just want to record the better picture and widescreen, analog sucks). After reading a bunch of topics, I am now more confused about HD capture cards. I am looking for something with hardware encoding to make it easier on the system(but is it needed? I heard that it is already broadcast in mpeg2 and dvd quality is fine for me) and something that has the tuner built in. I don't have a cable box, but the HD channels come in fine on my tv. So what would be a good card for me to get?

EDIT - added some info about my tv
My tv is a Vizio VX37L and has this under additional information (this is where I get confused on whether I need an hd tuner or a atsc tuner on the card)

ATSC with 8VSB & QAM demodulation
ATSC with MPEG-2 decoding
NTSC Video decoding via RF: Yes, thru Antenna, Cable, or Satellite
NTSC Video decoding via Video: Yes, thru CVBS, S-Video, or Component
Progressive Scan Video: Yes, thru Component YPbPr, VGA or HDMI
HDTV: Yes, thru HDMI or Component YPbPr
Computer: 640x480, 800x600, 1024x768, 1366x768 thru VGA/RGB or 640x480 thru HDMI