If Luthor is in it, I'd like to see an actor that is more "serious" than Matt Damon. If Denzel looked the part, he would be my top choice for Luthor. That should give you the impression of what Lex Luthor is like in my mind. If I could have any actor for the part, I'd like to see Daniel Day-Lewis or Sean Penn as Lex Luthor because those two, just like Denzel ooze intensity. They seem to be the kind of people that have such an intimidating demeanor and personality that you would feel smaller if you were talking to them. That is what I want to see in Lex Luthor, but in the same way that these guys could make you feel small. Not imposing in that Luthor can be explosive, or yells. None of that for Luthor, none of it at all. It isn't intimidating. Luthor should be intimidating in with that calm cool demeanor that seems so strong that it could make you feel small. The actors that I think could pull that off that have the right look for Luthor would be:
1) Daniel Day-Lewis
2) Sean Penn
3) Joaquin Phoenix
4) Ralph Fiennes
5) Josh Brolin
6) Edward Norton
Something along those lines, big name, but that have that fierce look and demeanor about them. I wouldn't want a guy that can naturally seem as nice as Matt Damon. The only one I wouldn't mind as Luthor that seems like such a nice guy would be Edward Norton because I know what seeing him play Lex Luthor would remind people of. Matt Damon, although he is good, I don't think would be taken seriously as Lex Luthor.