Landing an appearance by the president seems to be a game-changer at least for one show in late-night television. On Monday night, President Obama lifted David Letterman to his most-watched “Late Show” in four years, with a total of 7.218 million viewers. Here's the video from President Obama's appearance on the Late Show with David Letterman.  Talk of foreign policy, economic recovery, and health insurance reform is punctuated by a special gift of produce.  Watch It:Also. according to a new NBC News/Wall Street Journal poll, most Americans don't think Obama makes too many media appearances.  Just 34% say they see and hear Obama too much, while 9% say they see/hear him too little and 54% say it's the right amount.