Quickly, Kirby invented the vocabulary that Buscema used of action in every panel, characters posed in the peak of action, panel moving cinematically into the next panel, varying shots for maximum drama. He also developed whole catagories of comics including kid gangs, romance and superhero. He co-created most of the superheroes now being made into movies. Buscema might have been the most facile artist in the history of comics but beyond that most of what he did was done standing on Kirby's shoulders.
Jeez, granfalloon, that longer post above might be one of the most thoughtful, best written things I've ever read on Comicon.