Please post the cover you regard as a given artist's magnum opus, preferably from your own collection. Emphasis on Golden/Atomic Age but any era allowed, plus magazines, pulps and paperbacks as well as comics, and of course OA if you have it. Try to restrict yourself to just one per artist, but of course, cheating is expected and secretly admired.
To get us started, here are a couple I really like:
My favorite artist, hands down, and this may just about be his best cover, with many other really great ones to choose from. But this would remain my favorite even if I owned the other ones I really love. Hopefully we'll see a few of those posted here.