If the DOW goes to 16,000, what should you do? Warren Buffet decided to buy $3.4B of Exxon, citing it's low valuation! And investors are in a good mood Friday, a day after Federal Reserve chair nominee Janet Yellen told a Senate panel that she is determined to support the U.S. economic recovery, and believes the Fed's bond-buying program still has the power to help. But with the rescheduled Congressional Circus coming, it's not the time to let your guard down.