If we're talking all time artists, and not just in the sense of being an illustrator, but a creator as well, you'd be hard pressed to top The King. Many of the creations he had a hand in are still alive and thriving today, and his aesthetic has become a genre unto itself. He's also one of the first guys to approach the page as a canvas, not just a collection of little boxes with pictures in them. And he was prolific like a motherfucker too.

Not to mention he has a crackle named after him.

I could see this title also going to Will Eisner though, because like Kirby his contributions to the medium cannot be understated. His work is still breathtaking and his eye for design and typography was second to none. Kirby told stories about Gods, and Eisner was more concerned with the plight of the common man.

I also really dig Harvey Kurtzman for his diversity and especially what he contributed to the funny side of funnybooks.

Unlike with the writers list I guess I tend to look to the distant past for the GOATS, but some of my more modern picks would be Jeff Smith, Brian Bolland, Jim Lee, John Romita JR, Frank Quitely and Daniel Clowes