Best Video Capture Solution?

camperdave writes: I am in the process of building a system for a friend. She would like a video capture/TV tuner card of some sort. I have no experience with these devices, so I would like to get the opinion and advice of the Slashdot community. What are the advantages/disadvantages of using PCI based cards vs USB devices? Are there features to look for, such as mpeg encoding? Any caveats, thing to avoid?