Advice for a good TV capture card/device


I want to be able to watch and record tv on my computer. Right now I have a G4 533, with 4 open PCI slots, but I am thinking of selling this and getting a new powerbook. The only one I could find was My TV over at this website but I am leary of using a USB device to watch TV. I want to be able to watch full screen, and I am thinking that the video signal will have to be compressed if it was to go over usb, and I would like to have good quality. are there any firewire devices? or is a PCI video capture card my best bet? Thanks in advance for any insite.