A minor point perhaps to this interesting thread, but there is above an implication that the Canopus NX is a DV/HDV only card. My understanding is that it supports various other codecs for capture as well provided the capture is setup properly. BandH's list includes:
YUY2 (Uncompressed)-720x486/59.94i (NTSC), 720x576/50i (PAL)
Canopus Lossless-720x486/59.94i (NTSC), 720x576/50i (PAL)