Neither ! The most powerful of all ! PIZZAMAN !
It was always batman :) and always will be ... With lots of NA NA NA NA NA NA NA NA NA NA 's BATMAN !
While Superman seems to be somewhat of an American folk hero (like Europeans view their pagan deities), almost like an archetype, representing the early 40's consumerist (as an ideal to strive for..at least, appearance-wise), Batman stands for social marginality and spiritual desolation (intellectual's favorite) that pretty accurately represents the modern society. Superman is what the perfect world should be, Batman, meanwhile, is painfully true to himself. Both do great things in their own ways. Batman is more of a hero for our reality, though.