I started a couple years ago, trial and error and evolution, with a set top DVR, but also didn't just want DVDs, I wanted to edit in iMovie. I borrowed a friends Pinnacle to transfer and it worked well, but it runs $100 and I didn't have a lot of tapes and it wasn't worth that much to me. I ordered the iGrabber from Meritline.com for $20 or so, on sale. It works but the software was very awkward to get up and running, but I eventually figured it out. (They're is also a cheaper product-EZGrabber, for PCs that I wasn't able to get to work with the Mac.)
WIth Pinnacle & iGrabber, you are able to choose to have it shared with iTunes, so you can watch it immediately on Appletv via wifi, which can be convenient, until you get around to editing. The quality seemed pretty good with both, however, I haven't gotten around to doing much editing either.
I hope this helps you out.