For all the money in my ever-shrinking bank account, I would wager that the best superhero in all of fiction was created in 1962 by Stan Lee and Steve Ditko. Peter Parker, Spider-man, is the single most human and pure concept one could conceive of for a superhero. Superman's character is defined by his god-like goodness. His adventures play out on a cosmic scale while he simultaneously attempts to mimic the behaviors of a human being. His goodness is an innate part of his character and is never in question. The same goes for the character of Captain America, a character whose prime directive is to do "good." Batman represents the next evolution of this idea, in that his heroics are initiated by a particularly bad day in a dark alley.
Spider-man, on the other hand, is defined by his flawed humanity. Peter Parker's story illustrates the problems in believing in super-powers and the nerd wish-fulfillment that they might provide. He gets his powers, gets his revenge, and in his arrogance he ends up paying the ultimate price. Guilt fuels his heroics and eventually pushes him to realize exactly what it is that he has to do. "With great power must also come great responsibility," isn't just a saying, it is a religion. It is the Golden Rule.
