11. Amazo
What's better than a generic doomsday villain? A generic doomsday robot. Only Amazo is a spectacular threat in that he can learn from the Justice League, and harness their abilities against them. Fights with Amazo--and mind you it's a robot so there's more than one--can last a very long time. A good comparison is the final fight in X-Men Origins: Wolverine. The movie itself was lackluster, and it's pitiful excuse for Deadpool is insulting, but the fight itself was cool, especially how Barakapool harnessed all the previous mutants' abilities. A fight with Amazo could be massive. Super speed, lassos of truth, eye beams, all that good stuff, flying around, destroying everything in sight. The battle could be heart stopping and bone chillingly gigantic. Amazo lacks the pathos of a truly great villain, but damn he'd put up a good fight.