While we're on evil dictators, why not:
Stalin: Built an agrarian Russia to industrial superpower, BEAT Hitler, and laid the foundations for the Cold War. Also killed lots of people and never brought to justice.
Mao: Again, built a superpower, killed more than Hitler, and never paid for it.
And non-evil-dictators:
Einstein: Completely redefined out understanding of time and space with his Relativity.
Edison: Master of inventions, built GE, but his egotism hurt him in the end.
Newton and Leibniz: Calculus. Enough said.