Yeah in excess of 50 Gig per hour for pure AVI at 640x480 is my calculation, so a bit more again if you're at 720x576 which is DVD resolution. Still doesn't stop you using HuffYUV which is lossless, meaning that no information is taken out, just a mathematical algorithm is used to not have to repeat information that is the same from frame to frame : it's based on the same sort of idea as a ZIP file which can be smaller but is exactly the same file when you unzip it.

As for best capture cards, well I don't have the budget to try out funky hardware and I'm just using an ATi All in Wonder which does me fine. However I think the Canopus is highly respected in the more serious analogue capture stakes.