Matt: I know some covers are homaged so often that I get sick of them. Luckily, Sami Basri took a different path with this Power Girl cover, and referenced one of my favorite covers of all time, Excalibur #3. It doesn't hurt that Basri is a pretty good artist, and adds his own touches to the cover, such as the huge hole where Power Girl crashed.
Runner-Ups: Marvel Universe vs. The Punisher #2, New Avengers #3, Supergirl #55