Occupation: CEO, Google
A decade and a half after launching Google while a Stanford grad student, Page is a billionaire many times over, with a young family and a reputation as one of the great inventors in the Internet era. In other words, he's a prime candidate for early retirement. But Page isn't slowing down. Since replacing Eric Schmidt as Google's CEO last year, he has brought renewed urgency to the Web giant as it searches for a social-networking solution to rival Facebook while confronting increasingly thorny privacy and antitrust risks.