Another chance for a poll!
Neal Adams' cover for DC 100-Page Super Spectaculer #6 would seem to certainly be on the list of options for the Top 75 Most Iconic DC Covers. It was so famous that DC reprinted the comic in 2004, and it was ALREADY a reprint collection! That's how notable Adams' cover was.
However, Adams' cover is an homage to the cover of All-Star Comics #16 by Frank Harry.
So which one should make the list?
The original cover or the more famous homage?