1.) The M-Audio Fast Track Pro A/D converter adds a whole lot of bizarre rectified negative sine wave at around 5Hz. It's not horrible since I can take it almost completely out with a 50Hz low-pass filter, but that's a really bad artifact. I don't know if it's just my converter, if it's the driver, or what, but it's ugly. I'll have to do further testing.
2.) Dropping the audio on the timeline, I noticed a sample rate mismatch, meaning that the audio doesn't play at the same speed as the video-- it drifts. I'm too tired to figure out which is faster, and I'll have to actually resample the audio to get it to match, and I'll have to judge it by ear. Not happy about that at all, because that's a tedious-ass process.