Here's my list:

The Beyonder (Marvel) - He's a mutant and an Inhuman, with an insane amount of power. Like, he's not just a god... He's arguably the level of God, big G. He can literally manipulate the universe to be/do anything he so desires. That's a lot of oomph.

Lex Luthor (DC) - Always a classic villain, Lex has shown himself to be a master of ANY plan, including being one of he good guys when he sets his mind to it. A non-powered normal human who outsmarts one of the most over-powered super humans in all of fiction? Sign me up.

Yoda (Star Wars) - A teacher, a monk, a warrior and a diplomat... Yoda has a really well-founded set of skills. If you need to save the Galaxy, might as well go with experience, since he's done it before.

Sylar (Heroes) - A guy who can not only steal but improve/optimize any power he comes across? That's got "cheat codes" written all over it. Depending at what point you hone in on during the series, he also has the ability to do this WITHOUT slicing open the head of his target, so it's a win-win.

Bayaz (The First Law Trilogy) - Bayaz is the First of the Magi in the books by Joe Absrcrombie. He's one of the most powerful wizards in existence, he's immortal and he is one of the most tricky, manipulative and duplicitous bastards to ever walk the face of the planet. While serving his own ego and power, he also is shown to be doing all of this for the betterment of the world, in a way that only a powerful immortal being can really do, seeing mortal lives as the fleeting spurts that they really are to the history of the world.

Richard Rahl (Sword of Truth series) - Speaking of wizards, I'm grabbing Richard Rahl for one reason alone - he's the biggest Mary Sue in the history of fiction. In the off chance that the powers I am fighting against also get to pick characters, I want him off the board, as he can never, ever, EVER fail. In anything. Consider it a pre-emptive move in a fictional power arms race.

Henry Walton Jones, Jr. (Indiana Jones) - You want a guy who can rattle off pre-Mesopotamian societies from the top of his head and also boa whip his enemies into submission? Then look no further than this famous hat-wearing, whil snapping, Nazi-fighting archeologist. Also, his name is Henry (they named the DOG Indiana).