Winning the Nobel Peace Prize is likely to be more of a headache to President Obama than an honor. It reinforces the perception, held among many, that he is philosophically more European than American. And it's not hard to imagine the reaction should he decide to increase troop levels in Afghanistan - "Some advocate for peace!"
As a result, President Obama should refuse the Nobel Peace Prize. He should simply say, "I am honored and humbled by the decision of the Nobel Committee. But there are dozens, if not hundreds, of others who are far more deserving than I am." By doing so, he would reap the benefits (in terms of world opinion) of having been chosen for the award, but stymie critics by acting honorably and with humility and grace.