The stalwart defender of freedom, and mainstay of the Marvel stable, Captain America came out swinging in comics' Golden Age (KO'ing Adolph Hitler no less!), and packed a punch all the way through the Silver and Bronze Ages as well. The inspired creation of Joe Simon and Jack Kirby, Ol' Cap took down scores of Nazis, Commies and various other undesirables for over six decades before being taken down himself in 2007. According to Wikipedia:

"Captain America was the alter ego of Steve Rogers, a sickly young man who was enhanced to the peak of human perfection by an experimental serum in order to aid the United States war effort. Captain America wears a costume that utilizes an American flag motif, and is armed with an indestructible shield that can be thrown as a weapon."

"Captain America Comics #1 (March 1941) — on sale in December 1940, a year before the bombing of Pearl Harbor, and already showing the protagonist punching Nazi leader Adolf Hitler in the jaw — sold nearly one million copies.