There are loads...We have to think about the classic ones, than powers, battles, comic numbers, popularity, hero's personality and some more. Call me a fanboy but it's Superman. We can also put Batman,Spider-Man, Thor or (other favourite of mine) Captain America...
Many will say Superman because of his morals, his powers and his iconic status. Some will say Batman because of his realistic views on lifes criminals, on the way his humanity makes him strong. Id say its both of them. Superman is the light, the icon we all look up to. Batman is the darkness, that is not nessacarily bad, he just does what needs to be done. Superman is more "human" than batman is while bats is more "super" in terms as how they are protrayed. It like a yin yang thing. Both represent everything that creates a super hero and the greatest part one when put together. that just my opinion
Trivia: It was the moniker Superman that gave rise to fictional heroes with special abilities being called superheroes.
-Also the superman insignia is one of the top 3 most recognized symbols in the world.
- Superman has a plaque at the United Nations.
- Superman was used by the US Department of Defence as well as the United Nations International Childrens Emergency Fund (UNICEF) to spread info on Land Mines and their effects around the world. Commended by the Secretary General of the United Nations Kofi Annan, and the then US ambassador to the UN (Bill Richardson).
Anyways, I know it is just a matter of time before someone comes and says that Wolverine is the greatest superhero of them all, but to be honest Superman is simply on a league of his own here.
Simply put, the greatest.