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.
Desktop machine: 2 x Opteron 246, Asus K8N-DL, 2GB PC3200 ECC Reg., XFX GeForce 6600GT, 74gb WD Raptor, 2 x 19\" LCDs, Windows XP x64
Server machine: Intel P4 3.0GHz 2MB EM64T, ECS i865pe, 1GB PC3200, 36gb WD Raptor, Windows Server 2003
Laptop: Dell Inspiron 9100 (Intel P4 3.2GHz 1MB Prescott, i865pe, 512MB PC3200, Mobility Radeon 9700, DVD+R/DL Burner), Windows XP
Linux: P3 450Mhz, 386MB ram, Slackware 10.1 (Running mySQL/Apache)