When creating SD DVD's from HD clips (1920x1080 60i AVCHD), I've taken the advice of this group to add a "Sharpen" FX and setting the Sharpen Amount to "0".
Just for kicks, I bumped up the amount to 0.250 (the "Light" template) and noticed a definite improvement over the 0 setting. The "medium" template - 0.500 may be even better.
The effect appears to be the same on progressive videos for web distribution. The following was downsized from 1920x1080 to 640x360.
http://www.jazzythedog.com/testing/sharpen.aspx
I'd like to get the opinion of others. That is, the "Light" template is a visual improvement over Sharpen = 0
...Jerry