You're going to hear this alot: Batman.
Why? Well, before I hear an argument, here's the skinny.
In all his work, Bats has obsessively trained himself in numerous ways to better himself as a human being, largely because he understands his limitations. His weakness? Any human failing, and he works on it, unlike having a super power weakness that can't be so easily protected from. Even still...he has worked with a magician, a martial arts master, gotten into detective deduction, physically trained his overall strength and agility, and likely more. He has a great amount of legal resources to tap into to get what he needs...which includes a computer and series of vehicles which outmatch most military models by a great step.
Another important point is that he has made himself appear more than human by varying means, down to his suit, his gadgets, or his intimidation...but the point is that he created a mystique that has even criminal super villains quaking in their boots. He beats you because you don't know WHAT to expect...and when you expect him to be just another human being, he surprises the hell out of you. The gadgets, of course, allow him to deal with most any situation...like gas, water, fire, freezing, melting, cutting, lockpicking, heights, detection, and plenty more...such as numerous weapons he has practiced with to an artform. He has made himself seem unstoppable...and to those who think he isn't...well...he IS.
Take any sort of villain or, in fact, hero that he could face. Not only does he have a plan, or several plans, but he can also think on his feet very carefully. Batman is not just a major planner with a good follow-through, he can work them out quickly too. If he didn't, then all of the traps he DIDN'T expect in his life would have killed him. Oh wait, I seem to recall even DEATH not taking hold either. (That was a comic thing, of course.) This guy befuddles Darksied, Darksied who has a beam that will follow you to the ends of the Earth to vaporize you if need-be. He beat it, and he can outsmart anyone.