Bane all the way. Formidable, terrifying and intriguing.
Nolan's take on Bane, blows the comic book potrayals out of the water. Bane in TDKR is a terrifying fanatic, the very epitome of a super-villain terrorist and a walking juggernaut. The comic version was simply a big, overmuscled, hairy wannabe-luchador, Hardy's version is a real menace who doesn't need caricatural frame, to be imposing. The guy oozes voilence and fanatical conviction. One look and You know he means buisness. There is an aura of constant physical threat and utter ruthlessness about the guy (which I believe is far more in essence of the character, than just grotesquely huge musculature). Even his somewhat underdeveloped, rough physique attests to that. Hardy looks like a real thick-necked brute, not a clean-cut male model. There is even a promise of danger in the very way he moves, always walking, never running. Like a guy that knows what he is capable of and doesn't need to show off.
Unlike Joker who didn't give a **** about anything and was a chaotic anarchist, Bane has specific, ambitious plans for Gotham and is going to force them with practical, surgical violence and carnage. Bane in TDKR is someone who despite his great intelect, is nonetheless driven by some misguided and pathetic beliefs, that he is trying to force upon the world at gun-point. A mix between a neo-natzi militant and a romantic revolutionary. Hardy also brings a certain subtlety to the role. His eyes show intellect, his over-the-top, out-of-place voice brings a creepy quality to him. You can even see it in the way he handles and kills people. The scene where he murders Dagget is chilling. First he lightly places the side of his hand on Dagget shoulder, then touches him delicately, almost carresing him, finally he slowly grabs him by the face and breaks him.
Comic book movies needed a character like this. Every superhero movie is filled with ridiculous, flashy villans that are either unintentionaly silly, or simply bland. Bane works almost like the classical movie mosters, dominating every frame, while being interesting and terrifying at the same time.
Plus, he looked badass in that coat
But props have to go to Loki as well, as he is probably the most charismatic and fleshed out villian in Marvel films.