What's an acceptable .mpg and .wmv file size?
 

What are good file sizes for .mpg and .wmv files, 20 seconds long, that would be acceptable to link lists? I've made some .wmv clips from 1 MB down to 450KB and can't see a difference in quality.

WMVs are much smaller than mpegs with similar quality. If you can't see the difference in those file sizes then there is something wrong. Experiment more with your video editor settings...