Rank: 21
Bill Gates
Benefactor, Bill and Melinda Gates Foundation
Why He Matters: No, we're not talking about the guy who co-founded Microsoft. That Bill Gates plays an increasingly ceremonial role, taking "think weeks" in the woods while Ray Ozzie (see No. 10) charts the direction of the world's largest software company. Meanwhile, this Gates is spending more of his time leading the world's largest philanthropic organization. In just six years, the Bill and Melinda Gates Foundation, with a $29 billion endowment, has surpassed the World Health Organization as top global funder for health issues including HIV, malaria, and tuberculosis research, and has given away more money to charitable causes than John D. Rockefeller did in a lifetime. Hooray for that, and we wish Bill all the best in his new role.