I've had an ATI TV Wonder PCI card in my system for at least the last 3 years. Decent card for watching TV and such... I wouldn't pay a lot for once since the quality of any analog cable signal is going to be pretty crappy when displayed on a computer screen anyway...
That being said, my TV card has been one of the sources of major instability in my system since I've been running it. That is across 3 iterations of hardware and 2 operating systems. It even crashed a lot when I had a real All-In-Wonder card.
I haven't used any of the offerings from Hauppage or those guys, but I'm betting its probably about the same.
Unfortunately, Windows XP x64 doesn't support any of them at the moment, so I am running w/o one for now.