We already had a poll like this a while back.
I choose not to vote. I think ultimately you can't top The Joker, especially if you're just looking at it from a perspective of significance in Batman's history...but I truly adored Bane and don't want to contribute to his inevitable loss in this poll
Seriously though, they're entirely different archetypes. One is the trickster/devil/anarchist, the other is brute militaristic power mixed in with some revolutionary zeal. It's a complete 180 from The Joker and intentionally so. By being so different, the film is able to continue contextualizing The Joker in the mythology without ever mentioning his name.
Nolan on the main villains of the three films:
If you look at the three of them, Ra’s Al Ghul is almost a religious figure, The Joker is the anti-religious figure, the anti-structure anarchist. And then Bane comes in as a military dictator. And military dictators can be ideologically based, they can be religiously based, or a combination thereof.