should use to capture my old VHS footage in as much lossless quality as possible.
I have done lots of that.
To get your VHS video into iMovie, use the Grassvalley ADVC300 (It's much better than the ADVC110). With the ADVC300 Audio and Video go in, FireWire comes out. It also comes with a nice Macintosh application that works flawlessly with iMovie 06 and iDVD 09/11 (I have used it a few times with iMovie 11).
The program that comes with the ADVC300 has some nice filters that can improve video and audio of the source material. The ADVC300 will take Audio and Video from any source (VCR, Tivo, Satellite Receiver) and convert it to FireWire (iMovie will treat it like a camera).
I've played around with countless other conversion systems, ranging in price from $79 to $399. Short verison, this is the ONLY unit to own. No dropped frames at all, even with questionable quality tapes, no jitter, great color, excellent sound quality. Zero setup with iMovie 06 and iDVD 09/11.
This is a prosumer deck. The time code function is alone worth the price if you have old analog footage. Absolutely NO "Out Of Sync" audio.
ADVC300 is for anyone who wants to do editing and is concerned about quality of color and speed, for the novice it is an incredible gizmo that will restore VHS tapes to a state close to the original fixing midtones, highlights and shadows on the fly. Not only can you simply convert analog to digital you can actually manipulate the signal going in (if you want to).
http://www.videoguys.com/Item/Grass+Valley+ADVC300/035303230363.aspx
I would use iMovie 06 with iDVD 09/11, why?
iMovie 09/11 uses 'single field processing' meaning every other horizontal line of the video is thrown out, which reduces the sharpness of the footage. iMovie 06 uses ALL of the image to form the video.
If your primary workflow is editing DV clips and making DVDs, iMovie '06 is better suited. Your movie will arrive at iDVD in DV format, which is an ideal match for making a DVD: same resolution, same pixels aspect ratio, and original quality. If you share your movie from iMovie 09/11, it gets re-rendered at 640x480 or less, and then iDVD upscales it back to 720x480. The end result is obviously not as good.
iMovie 06 and iDVD 11 is a "lossless" combination.