Steve Ballmer
Microsoft CEO Steve Ballmer. Age 54. Ballmer is arguably the world's hardest-working and most animated billionaire. The Microsoft chief executive is a salesman extraordinaire who will go to any length to sell a product - and in the process, often makes a complete fool of himself. In spite of his bombastic displays, Ballmer is nobody's fool: he leads the world's biggest software company, and Forbes estimates his personal net worth at $ 15 billion.