I installed the USB 2.0 card (replacing the old 1.1 card I had in there before), and installed the internal flash reader. The latter was kept unplugged, though, until I could install the drivers for it. I didn't realize at first that 2000 didn't support USB 2.0 out of the box, though, so off I was to M$'s update site to get drivers (after a bit of searching to find out where to go).
After (I thought) I had the new card working, I installed the drivers for the flash reader and plugged it in. Everything was going fine with it finding the drivers, until it was just about done and the machine completely froze. It took hitting the reset button to get anywhere after that. At first, I thought it was just the card reader, so I tried installing the video capture device and got the same result. The symptoms were exactly the same, and there was one common denominator... the USB 2.0 card.
I put the USB 1.1 card back in, cleaned up the installed drivers a bit, and tried installing the video capture device. It worked! I did the same thing with the flash reader, with the same result. I'm not sure if it was something with the card, or with Microsoft's updated USB driver, but something in that mix was not right.
Since both devices support USB 1.1 as well, I can live with that for now. The video capture device did say that the video quality was 25% better with 2.0, so I'm going to shoot some video sometime this week and see just how it looks at the moment. I'm not going to be pumping S-video into the thing for a while, so I'm not too worried... NTSC composite video isn't that great to begin with :-)
I guess the moral of this story is, don't buy cheap hardware from no-name manufacturers. I was lucky in this case with the flash reader, but not so much so with the card.