10) Sheila Bair. By arguing that the federal government should do more to modify troubled loans--and then introducing a program that would do so--Bair, who heads the Federal Deposit Insurance Corp., has emerged as a leading figure in the high-profile battle against foreclosures.
11) Kenneth Lewis. For now, Bank of America CEO Kenneth Lewis remains in charge of the consumer-banking giant. After losing face following unexpected losses from the $21 billion emergency acquisition of Merrill Lynch, he's fighting to restore the bank's profitability--and his reputation.
12) Jamie Dimon. The J.P. Morgan Chase head is either the smartest guy on Wall Street, or just the luckiest. He got the deal of the century by picking up Bear Stearns and Washington Mutual, deals which makes Morgan, by some measures, America's biggest bank. Now all he has to do is rebuild destroyed shareholder value at a time when a slow economy and tighter regulation could make banking a far less profit-friendly business.
13) Vikram Pandit. Citigroup's beleaguered CEO has a tough year ahead (if he manages to keep his job). The looming questions: What's to be done with a $306 billion portfolio of troubled mortgages and other assets? And will the bank weather mounting credit card losses and consumer defaults?
14) Jim Cramer. Love him or hate him, the former hedge-fund manager turned "Mad Money" host on CNBC still has a voice that out-booms all others when it comes to stock picking. Lately, his manic antics have included scathing attacks on asleep-at-the-switch regulators and tossing his hat into the ring for the job of chairman of the Securities and Exchange Commission.
15) Prince Alwaleed bin Talal. The billionaire Saudi investor has had a rocky go since his firm, Kingdom Holding Co., went public on the Saudi stock exchange in 2007. A huge stake in Citigroup went south last year, sending Kingdom shares down 62 percent. Alwaleed's personal net worth slumped to an estimated $17 billion, down from $21 billion in 2007.
16) Eric Schmidt. The Google CEO is forging ahead despite a wavering stock price on the strength of a 60 percent-plus market share in Internet searches and the accompanying highly profitable ads. He's also behind new moves into coming battles in the browser and smart-phone wars.
17) Meredith Whitney. Oppenheimer's outspoken banking analyst has become the closest thing to a household name in the research world, thanks to gutsy but accurate forecasts of financial trauma. Her bearish calls made her one of the most prescient figures on Wall Street and influential enough to make blue-chips tank and CEOs tremble.
18) Steve Jobs. It's hard to think of any company more tied to the personality of its leader than Apple. It's not surprising, given Jobs' role as the architect behind runaway successes including the iPod, iTunes, and iPhone. A swooning share price amid rumors regarding his future at the company shows Wall Street still believes Apple's fate rests on the man who made Mac.