I've had great luck with a MCE box plus HDHomerun plus 3 analog tuners, all pulling signals from analog, $16/month cable (HD via clearQAM; that's where most of my content comes from). I'd strongly recommend it. About $160 for the HDHomerun, about $130 for the dual Hauppauge card, and I think I paid $40 for the Asus card (the third analog tuner).
No additional fees, no funny business, works flawlessly. I don't use the computer much for anything else, so it's a bit wasteful (most of the time it draws power and sits there doing nothing...) but it works well and feeds my XBOX360 wirelessly, attached to the 42" Panasonic plasma.
If I were to start over in doing this, I'd probably get the cheapest Mac mini, throw Vista Premium on it, network it to the HDHomerun (2 HD clearQAM tuners), and attach a 500GB USB drive to it, buy a Media Center remote, and call it a day. Tiny size, easily enough horsepower, less wasteful. But the other machine was bought and paid for.
