Best format to capture video with greatest flexibi

What is the best format to digitally capture video from video tapes for backup & the eventual conversion to whatever format that is yet to be decided? I.E., which format & codec is the easiest & least likely to lose quality when converting to either PAL/NTSC MPEG2, DivX, etc.?

I'm thinking that an uncompressed format is not too good because of storage constraints; I wondered how much space an hr of uncompressed video will take, 100GB/1000GB/10000GB? Is MPEG-1 with a very high bitrate the best best? The source isn't that high-fidelity though, since it's from a video tape (as opposed to a DVD), so I guess the capture doesn't have to be in a very high resolution?

My machine (Cel366+256RAM) can't handle MPEG-2 capture & quality conversion. I'll do the conversion when I could afford better hardware. I am getting a 200GB drive w 8MB cache though, to replace my currently dead HDD. I need to backup all my tapes within the next couple of wks. My video card is an ATI Radeon All-In-Wonder card.

The <i>most likely</i> eventual format would be a very high compression codec that can retain excellent quality video (like perhaps DivX, MPEG-4, WMF, etc., although I don't really know their differences).