Depends on if you want to edit or not. If you are just copying to dump to DVD or VCD, ADS' USB instant DVD will work. If you have a Sony camcorder, depending on which model, you could modify it via software/jig or Sony RM95 remote to run analog into the camera and send the signal via firewire out to the pc. It will also work in reverse (firewire into camera then analog out the video and audio ports. You use the Rm95 to modify several ram addresses which enables the analog inputs rather than the camera input. (Do at your own risk...).
Capture the video as plain ol' DV footage if you can (you'll need an A/D converter, like Dazzles Hollywood Bridge, if you haven't one already). It's the fastest, most reliable, and efficient standard you can use in Vegas. DV also prints perfectly to digital sources (theoretically, anyway), but it also prints real well to VHS recorders (with the help of a D/A converter). As the format exceeds the specifications of VHS, it makes for a real nice "mix down".
If that's not and option for you, hardware MPEG encoders (like the Dazzle DVC) can also capture some VERY high quality stuff. The resolution is about half that of DV, but if you're going to port everything back to VHS anyway, it's a perfectly viable option. There’s still enough headroom to create a nice mix down. When working with stuff inside Vegas however, you still may want to batch convert everything to DV, as you’ll get the best result when manipulating the video.
Anyway, that’s my two cents. I’m sure a lot of other Vegas users will be able to contribute some helpful advice to this conversation.