For consumers, rising prices are no fun. But when it comes to investing, they can be the key to choosing winning stocks. No less an authority than Warren Buffett has said that the ability to hike prices is the single most important factor to consider when evaluating a business. "Pricing power is the key to sustainable earnings growth," says Vadim Zlotnikov, chief market strategist at AllianceBernstein. "There is clear evidence that shares of companies with pricing power dramatically outperform their peers." With that in mind, here are three Fortune 500 companies that have proved their pricing leverage.