It may not be the growth stock it once was, but there's still has plenty of fuel left in the tank.What is Warren Buffett's favorite stock? Other than the company he chairs, Apple (AAPL -1.41%) may well be at the top of that list. The iPhone maker has been one of Buffett's largest holdings for years, even as he has decreased his stake in the tech company over the past 12 months.Regardless, Apple remains a top stock to buy, and thanks to ongoing development and progress, the company could deliver market-beati ...