NEW YORK (Reuters) - Barack Obama topped Forbes' list of the world's most powerful people in 2011, as the US leader's clout rose after the deaths of al Qaeda leader Osama bin Laden and Libyan dictator Muammar Gaddafi. Obama bumped Chinese resident Hu Jintao from the No. 1 spot on the magazine's annual rankings. German Chancellor Angela Merkel remained the most powerful woman at No 4 on the list, as Europe's largest economy continued to wield its influence over the troubled European Union. Russian Prime Minister Vladimir Putin, who is running again for president, was No 2 and Hu came third as he gradually manages the transition of power to others in China.