Let the hive mind of Engadget get that for you.
"I need help! I want a small pocket camcorder but I'm not sure which one to get. I don't want to fall into the hype of the Flip because I worry two hours won't be enough. What should I be looking for when considering a small camcorder and where can I get a good quality one with expandable memory? Thanks!"
The reason it doesn't matter is because the TiVo doesn't even have the power to take advantage of the 100Mbps nic it has now.
As for playing HD on a PC, I used to do it with a P3 700 and a Radeon 9500, so any video card sold today will work fine.
But even if you do want the latest, you can buy a Radeon 2600XT for less than $100, which is less than 1/3 the price of a TiVo HD.