Lex Luthor is being rumored as a villain to appear in the sequel to "Man of Steel".
Kevin Spacey.
Spider-man would beat him up until he decides to stop calling him an idiotic spider. Spider-man would break his kryptonite suits and then stop Lex Luthor by webbing him to jail and go away.
Iron Man would win because Tony has a lot of Iron Man suits and can summon them whenever he needs to even all at once. Lex Luthor's suit is able to take down Superman only because his suits are based on kryptonite. Stark also knows more physical hand to hand combat.
Bryan Cranston
Nuclear Man- who was created by Lex Luthor.
Lyle Talbot
Mark Strong
Joaquin Phoenix
Denzel Washington
Lex Luthor is a mortal man and does not have any powers. He does have an armored suit powered up by kryptonite so he can fight Superman and actually hurt him.
In the DC Comics world, the first smartest man alive is considered to be Lex Luthor, a supervillain and frequent adversary of Superman. The second smartest man is typically portrayed as Batman, also known as Bruce Wayne, due to his exceptional detective skills and strategic mind.