In some ways, Ken Griffin, the founder of Citadel Investment Group, is an ordinary hedge fund pro. He's rich, collects art, lives in a swanky pad, and he's on the secretive side. But what distinguishes him, according to Fortune, is his ambition. A lot of hedge fund guys just want to get rich and live accordingly. But Griffin is either a visionary or a bit megalomaniacal if you know what I mean. He's not aiming for a good name like Tiger Management's Julian Robertson or SAC Capital's Steve Cohen, he's out to build a company on the scale of a Goldman Sachs. Few people think of his firm in those grandiose terms, but a guy's got to think big. There was a time when some thought Bill Gates was off his rocker. Certainly, Citadel has a good reputation as a quant fund.

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