Bill Gates has given away billions* of dollars. He has been a leader in the global fight to eliminate polio. While I have never been a fan of Microsoft or many of its products I will be the first to say Bill Gates has been using his vast fortune to make the world a better place!
Mind you I am still using Linux as my desktop.
*I think he has given away more than 30 Billion dollars via the Bill and Melinda Gates foundation.