I know there's a heap of PCI capture devices & graphics cards that can capture to uncompressed full res video, but my experience with them has been that they're always hassle due to the drivers being a complete pain, plus the fact the video signal has to go straight to the computer so there's more chance of RF inteference.
I like my Canopus ADVC-100 because it's external plus I get great capture from it but it's DV so it's already compressed by the time I get to use it and I'm just curious to see what else is out there.