Alan Turing had of the greatest minds in computer science. To him we owe not just artificial intelligence but also modern computing (among numerous other ideas and innovations). And yes, he led the efforts to crack German Enigma codes that shortened WWII by two years and saved millions of lives (according to one Dwight D. Eisenhower).
A thankless job you say? Not at all! His reward was the destruction of a passionate career, professional marginalization and criminal charges that led to the ignominy of chemical castration all of which cast an indelible shadow over his life's work. Humiliated and legally bound to secrecy, his depression and suicide hardly made the news since he was a relative unknown when he took his own life at age 41 in 1954.
To be fair, the British government promptly issued an apology for "what happened to him"- in September 2009 - "on behalf of all those who live freely thanks to Alan's work". Just so you don't think they don't care, you see? Public petitions to grant him a posthumous pardon continue to be rejected. Because you've just got to draw the line somewhere: war heroes can't be allowed to get away with being homosexual. No sir!
Oh and did I mention 2012 is Alan Turing Year? Enjoy!