David Cameron press regulator
Title: Prime minister, United Kingdom
Age: 46
In the two years since taking office, the Tory prime minister has gone from being called the second coming of Margaret Thatcher to standing in the shadow of Europe's new Iron Lady, Angela Merkel. Cameron rejected the German chancellor's call to increase the European Union budget and threatened to veto anything but a spending freeze.
At home he faces a sustained economic downturn, a disillusioned electorate, and rumblings from his own party over Britain's future.
Xi Jinping: Peng Liyuan pop icon
Title: General secretary, Communist Party of China
Age: 59
The man who will lead China for the next decade was recently promoted to the Communist Party's top position; Xi also took over as chairman of the party's Central Military Commission, putting him in control of the world's largest army.
His rise to power will be complete in March, when he takes over for Hu Jintao as president and head of state. Xi is only half of a Chinese power couple: His wife, Peng Liyuan, is a superstar folk singer.
Mario Draghi: Eurozone Crisis
Title: President, European Central Bank
Age: 65
With the eurozone lurching from crisis to crisis, the European Central Bank is more important than ever. As chief banker of the world's largest-currency area -- the eurozone's collective gross domestic product is more than $17.4 trillion -- Draghi faces the Herculean task of trying to maintain financial unity across 17 countries.
But if anyone can wrangle the interests of nations as diverse as Germany and Greece, it might be the man who navigated the minefield of Italian politics so deftly he earned the nickname "Super Mario."
Abdullah bin Abdul Aziz al Saud: Arab Spring Saudi Arabia
Title: King, Saudi Arabia
Age: 88
The absolute monarch of the desert kingdom controls 20% of the world's known oil reserves and guards Islam's holiest cities. The Arab Spring didn't shake the ruling family's control of the kingdom, but out-of-control youth unemployment remains a threat.
Aging Abdullah lost his second heir apparent in two years when his brother Crown Prince Nayef died in June. He has been replaced by another brother, 76-year-old Crown Prince Salman, the former governor of Riyadh.
Ben Bernanke: Fiscal Cliff
Title: Chairman, U.S. Federal Reserve
Age: 59
Bernanke has led the Federal Reserve on a buying spree: In a third round of quantitative easing, the central bank is snapping up $40 billion a month of mortgage-backed securities and $45 billion worth of Treasurys. The result is a modest economic recovery and a near-record $2.9 trillion on the Fed's balance sheet.
The American economy's "adult in the room" recently warned that there is only so much the Fed can do; Bernanke wants politicians to take the initiative needed to keep the country from going over the fiscal cliff.
Benedict XVI: Pope Benedict XVI Twitter
Title: Pope, Roman Catholic Church
Age: 85
How's this for a job description? According to the doctrine of papal supremacy, the pope enjoys "supreme, full, immediate and universal power" in the care of the souls of 1.2 billion Catholics worldwide. They turn to the Vicar of Christ for the final word on life's most personal decisions, including birth control, abortion, marriage and euthanasia.
As the leader of Vatican City, he's also a head of state. Of course, the pope does face dissent -- recently from "radical feminist" American nuns.
Bill Gates: The Giving Pledge
Title: Co-chair, Bill & Melinda Gates Foundation
Age: 57
The world's second-richest man is worth $65 billion -- and that's after having given away more than $28 billion in various philanthropic endeavors. Gates' post-Microsoft mission includes eliminating many infectious and deadly diseases. By his estimate, that could translate into 8 million lives saved by 2020. (Microsoft publishes MSN Money.)
But the quintessential activist billionaire doesn't stop there: Gates continues to persuade his billionaire peers to sign the "Giving Pledge," promising to give away at least half of their wealth.
Vladimir Putin: Vladimir Putin KGB
Title: President, Russia
Age: 60
Re-elected in March to a third six-year term -- a tenure interrupted by a few years spent swapping posts with Prime Minister Dmitri Medvedev -- Putin officially regained the power no one believes he truly relinquished. This October, the ex-KGB strongman, who controls a nuclear-tipped army, a permanent seat on the U.N. Security Council and some of the world's largest oil and gas reserves, turned 60. That's Russia's retirement age, but who's got the nerve to tell him to quit?
Angela Merkel: World's most powerful women
Title: Chancellor, Germany
Age: 58
The world's most powerful woman is the backbone of the 27-member European Union. Merkel carries the fate of the euro on her shoulders. Her hard-line austerity prescription for easing the European debt crisis has been challenged by hard-hit southern countries as well as nations in the more-affluent north, but Merkel has stayed the course.
Merkel has served as Germany's chancellor since 2005. One of her biggest challenges lies ahead: bolstering her government's sagging popularity before the 2013 general election.
Barack Obama: Obama's second term issues
Title: President, United States of America
Age: 51
Obama was the decisive winner of the 2012 presidential election on all counts -- he prevailed in the popular vote, dominated the electoral college and won nearly all of the swing states presumed to hold the key to the election outcome. Now Obama gets another four years to advance his political agenda.
The president faces major challenges, including an unresolved budget crisis, stubbornly high unemployment and renewed unrest in the Middle East. But Obama remains the commander in chief of the world's largest military and head of the sole economic
Full profile at Forbes.com
