Interesting observations, Michael, and not too surprising. As has been pointed out many times, although scaling the 480 material on a regular DVD up allows a full picture to be shown on a 720 or 1080 display, the "real" resolution isn't increased and is still 480. So, an HD disc should look at least a little sharper if other factors in the production are held constant(some other factors might be improved in a newer disc, independent of the higher resolution). By the way, you should be prepared for the PMs you might be getting, requesting the regular DVDs that you'll surely not be needing anymore.
