Investors shouldn't unthinkingly follow Buffett, or any other billionaire money manager, into Amazon or any other stock. However, Amazon is a top stock with robust opportunities trading at an attractive valuation, and if you have $500 available today, Amazon is an excellent choice.

Warren Buffett has generated tremendous gains for the long-term shareholders of Berkshire Hathaway over the years. The Berkshire Hathaway portfolio today features stakes in more than three dozen companies that were either selected by Buffett himself or one of his investing deputies.

Among Berkshire Hathaway’s largest holdings is a financial information-services company. The sector’s results speak for themselves.

Warren Buffett is a famous billionaire investor, and his trillion-dollar conglomerate, Berkshire Hathaway (NYSE: BRK.A)(NYSE: BRK.B), owns nearly 50 stocks in its portfolio. Several of these stocks are in the financial and energy sectors.

The latest Berkshire Hathaway 13F filing came out last week detailing the holding company's buys and sells, and there were a few surprises. Warren Buffett waded into Pool Corporation (NASDAQ: POOL) and munched on Domino's Pizza (NYSE: DPZ) for the first time.