At the risk of being stoned to death as an infidel, I disagree. I give Kirby his due for possibly being the fastest comic artist, the one the most ideas, a risk taker, but IMHO his artwork to be crude, jarring, and, well, just plain old ugly.
I think you answered the question by your response. Who else could being stoned to death for omitting is there?
I mean, Im taking the thread title to mean..... who is the GREATEST, not who is my favorite.
Kirby did it all, for the longest, and with the most publishers, and even served in WW2 !! That's of picture of greatness in my thinking