1. Michael Fassbender
A near perfect fit, Michael Fassbender also just happens to be one of the best actors in the world (I ranked him #2 on an earlier list of best actors). While he is already currently involved in another superhero franchise, the X-Men movies where plays an excellent Magneto, he would still make the best option to play The Dark Knight. Fassbender has shown in several films that he can play a variety of roles, including a tortured addict in Shame and an intense anti-hero in X-Men: First Class, both of which show him playing characters similar to what is needed out of an actor taking the role of Bruce Wayne. Versatile, intense, charismatic, and dedicated, Michael Fassbender possesses all the traits needed for both Bruce Wayne and Batman, and could give a potentially iconic performance in Justice League as the Caped Crusader.