My captures, done with DV AVI, take 30 GB's. DV AVI has a 1:4 compression ratio, so that's around 120 GB's using composite video. Laserman's are 200 GB's, but that's with component video - much more video information to store.
BTW, my numbers include the analog audio interleaved. The PCM audio, on a separate capture, takes about 1.27 GB's. This is why I turned it into a DD 5.1 sountrack, which only takes 387 MB's.