The Hulk!
Yeah, he's more of a force of nature than a hero. But hear me out.
Take Superman. The last son of Krypton, delivered to a humble family and raised to be goodness personified, a living symbol of what mankind can aspire to be.
Now take the Hulk. A creation of mankind's mistakes, sympathetic but dangerous, tragic and flawed. He can be every bit as dangerous and destructive as the forces that oppose him.
Superman is God. He comes down from the heavens to deliver us from evil. His power is almost absolute and he will never faulter in his duty.
The Hulk is defiance. He is mankind raging against everything that tries to hurt it. He will not be defeated, he will not be stopped, he will fight harder and harder until he finally has peace. And while that force can be dangerous, he is balanced by the other side of humanity: Bruce Banner, who like the Hulk is a tragic figure, flawed, but ultimately only wanting peace.
And as flawed as he is, I would rather have the Hulk than Superman. Strange as it sounds we can learn something from Hulk's defiance, we can see ourselves reflected in his rage and know we are flawed, but can also be a force for good. Superman may be a symbol of good, but we have yet to learn any real lesson from him other than the belief that he will always be there to save the day for us.