Warren Buffet
AGE: 76
OCCUPATION: CEO Berkshire Hathaway
NUMBER OF TIME COVERS: 0
PREVIOUS APPEARANCES ON THE TIME 100: 1
PRO: Perhaps the smartest investor alive, and the second richest man in the world, worth roughly $52 billion. He announced plans last year to donate his fortune to charity, giving 83% of it to the Bill and Melinda Gates Foundation.
CON: He's set to retire.