AMD dual core 64, 4 gb ram, xp 64 pro. For me it was the ram that got in the way with one product... wouldn't support > 3 gb. Card I use accepts all cable/sat input as well as over the air, which is what I use... I don't "pay" for TV. In my local area there are 51 channels of over the air... and so little time to watch 'em all. :)
What makes the difference is 24" or better widescreen lcd at 1680x1050x32 for that true HD experience. Also helps to have kick a$$ sound, which I do since I am a musician when I'm not piddling with webworking.
Ultimately I ended up on the "high end", but even so, that was way less than the price of a similar size lcd hdtv.