But if you look at a Rockwell work and compare it side by side, Rockwell is an "illustrator" in style, where Robert's work is painterly. It's hard to explain but easy to see.
I'm including a photographer or two in my list of the artists I like. I'm forgetting some, but...
Fastner & Larson
As a visual artist, I can't just pick one. But of all the great American artists of the second half of the 20th Century, I would have to pick Chuck Close and Robert Rauschenberg as the ones that have influenced me the most.