Berkshire Hathaway (NYSE: BRK.A)(NYSE: BRK.B) CEO Warren Buffett is arguably in a class of his own when it comes to investing legends. Since taking the helm of Berkshire Hathaway in 1965, the Oracle of Omaha has led his stock to an average annual return of 20%. Taking into account the 20% year-to-date gain for Berkshire's Class A shares (BRK.A), shareholders have seen Buffett generate aggregate returns of almost 3,400,000% in 56 years.