I used the "High Quality NTSC" setting, which is 640 X 480, 16 bit stereo. I was surprised it didn't look a little better than it did, too. I'm spoiled by watching it on the DVD. I guess I could have used one of the HDV or HD settings for the WMV, but can't imagine the size at those settings.
Even at 640 x 480, it's still a 480+ MB file. I started the generation when I left for work, and it finished shortly after I got home. Then, it took several hours to upload. (I'm not sure exactly how long, because it was still going when I went up to bed.) I also figured it had to be somewhat managable to fit on people's computers when they want to watch it.