I gave VirtualDub a try, and the quality pretty much looked the same. It must be a limitation of the cheap capture device I'm using. I do like that I can compress the video as I capture. So instead of 30 minutes taking up 5+ gigs, it'll only be a couple of hundred megabytes.
I also gave PowerDirector a whirl, and pretty quickly uninstalled it. It's just way too much price and feature-wise than I need. Avidemux does what I need, and I also figured out how to queue up projects. That let me run them overnight instead of taking up all my CPU while I'm trying to use the PC.
I still need to tinker with the audio capturing. After that, it'll be smooth sailing.