The power of Warren Buffett is impressive. He decides to invest a few billion in Goldman Sachs and panicked investors calm down. And why not? Nobody has an investing record that can even come close to comparing with Buffett's record: he is the lone outlier of Wall Street. According to most calculations, since 1951 Buffett's Berkshire Hathaway has generated an average annual return of about 31%. The average return for the Standard & Poor's 500 over that period is 10% a year. The stock market...