Around 12:45pm EST today, Apple (NASDAQ:AAPL) was the most valuable stock in the world, topping the current king of stocks Exxon Mobile (NYSE:XOM). When Apple rose to a high of $369.89 per share it had a $342.8 billion market share, and when Exxon fell to $68.78 per share it had a $334.41 billion market share.  This ...