The 50 people who matter today: 1-10

The top 10 on our diverse list of individuals, couples and families changing the world, for good and

1. The Obamas

First family

It is easy to be beguiled by the visual power of America's first family. The Obamas' presence in the White House projects to the world a version of the all-American family that is the polar opposite of their predecessors, the Bushes. From the family's resolutely urbanite profile to Michelle's slavery roots, from Sasha and Malia's photogenic charm to their parents' combination of style and intellect, the Obamas have a universal appeal and something the Bushes never had - cool.

Yet the circus around the Obamas can detract from the deeper significance of their success. The election of the first African-American president has changed the US for ever, and his progressive policies continue along this path. It has not been easy - health-care reform has been his most intractable challenge to date - but the decision to close Guantanamo Bay and the abandonment of plans for a missile defence shield in eastern Europe have transformed the US's reputation and its relationship with the world.

But it is more than just policy, or office, that makes Obama so influential. The man is normal and relaxed. He can write honest, beautifully nuanced, intelligent prose. When he smiles, it is genuine rather than pained. These are superficial qualities, perhaps, but his magnetism, and that of his family, gives them huge cultural power. So does their obvious symbolism.

2. The Murdochs

Sky lords

In his book The Murdoch Archipelago (2003), Bruce Page, a former New Statesman editor, observed that the liberal Guardian, the
illiberal Mail and the neutral BBC all resemble one another more than they resemble any Murdoch product: for all their differences in political standpoint, they strive to maintain an independence of the state.

The Murdochs' News Corporation erodes the boundaries between state power and media operations. The same could be said of Silvio Berlusconi and of numerous authoritarian regimes, but the Murdochs alone cross international boundaries, influencing popular perceptions of reality (there is no other way to put it) from Montevideo to Manchester, Baltimore to Beijing, and always getting close to the seat of power.

In a world where information is the most precious commodity, the Murdochs - through interests that cover newspapers, television, radio, books and the internet - control their own global superhighway. They summon aspirant political leaders such as Tony Blair and David Cameron to address themselves and their leading executives, judging whether they are worthy of support. Despite contrasting editorial styles, the Murdochs' papers (and broadcasting outlets) express a unanimity that Page describes as "the intellectual equivalent of synchronised swimming". No Murdoch paper or magazine opposed the Iraq invasion, though some (Modern Fishing, for instance) didn't express a view. No Murdoch organ doubts the merits of free markets. All attack the "statist" BBC. To a remarkable extent, the Murdochs' agenda - light business regulation, tight shackles on unions, a semi-detached relationship with the EU - is also the British political agenda of the past three decades.

Unlike many past media tycoons, the Murdochs are rational business people. What drives them is power and control, not a specific political programme. Their first priority is to secure News Corporation's business interests, suppressing all potential rivals and regulatory threats. If anything, they prefer pliable centre-left parties in order to close off more hostile options. They prefer relatively untried leaders, as Thatcher and
Blair once were, as they have greater need of their support. Once secured, that support is unstinting, but it is always conditional.

We must now speak of "the Murdochs", as James, the fourth of Rupert's six children, has taken charge of News Corporation, Europe and Asia, overseeing, for example, the company's British newspapers (which boast more than a third of total national newspaper circulation) and Star, the TV satellite operation in Asia. Murdoch père, at 78, still calls most of the shots, but James, 36, has made his own mark. He takes global warming seriously, and the Times and Sun, previously inclined to the sceptics' camp, suddenly switched to firm support for reducing carbon emissions. No global warming denier now gets significant space in the Murdochs' papers. The calculation, no doubt, is that a drowned world would be bad for News Corporation's prospects. We may yet have cause to be thankful for the Murdochs' cold, calculating assessments of what's best for business.

Peter Wilby

3.Marwan Barghouti

Palestinian Mandela

Marwan Barghouti may be a detainee in an Israeli prison - a leader of the second intifada, he was sentenced to five life terms in 2004 - but hopes for peace in the Middle East rest on his shoulders. Many Palestinians regard him as an antidote to the corruption of the Fatah Establishment, and a number of senior Israeli politicians believe he is the only man who can unite the Palestinian sides and reach a final-status agreement with Israel. Touted as the "Palestinian Mandela", Barghouti is expected to launch a presidential campaign in 2010.

4 Eric Schmidt, Larry Page and Sergey Brin

Search party

Is any brand more ubiquitous than Google? Eleven years after it was founded in a garage in California by Larry Page and Sergey Brin, now headed by Eric Schmidt, it is the defining company of our internet age. It weathered the economic storm better than many analysts expected, further extending its domination of the search-advertising market.

5. General Stanley McChrystal

US super trooper

US military commander in Afghanistan since June, Stanley McChrystal is spearheading the fight against the Taliban. Despite having compared western strategy in Afghanistan to a lumbering bull, he insists that the situation could be remedied with more money and a reduction of civilian casualties. McChrystal is the man to whom Gordon Brown and the Ministry of Defence will look for guidance on Afghanistan. He will also determine the need for further US or Nato troops.

6. Malalai Joya

Afghan heroine

Assassination attempts and death threats have not silenced Afghanistan's answer to Aung San Suu Kyi. The 31-year-old, the youngest person elected to the Afghan parliament in 2005, was expelled in 2007 for speaking out against the warlords who maintain a grip on power under the western-backed government of Hamid Karzai. Forced to live like a fugitive in her own country, she fights on from the secret hideaways of her supporters, exploding the myth that the war has liberated Afghanistan and its women. With her new memoir, she has become not just the "voice of the people of my country", but a figurehead for peace and demo­cracy campaigners around the world.

7. Vladimir Putin

Russian bear

Russia's prime minister and former president is credited with bringing the country back from the brink of collapse and increasing GDP sixfold. Russia's strategic importance has also grown under Putin, who disregards diplomatic niceties as he reasserts the presence of his country - with its 12,000-plus nuclear warheads - on the world stage. Putin's formidable influence shows no sign of waning; he has hinted that he could return to the Kremlin in 2012.

8. Osama Bin Laden

Terrorist-in-chief

The latest message from the al-Qaeda leader has thrust him back into the public view at a time when his group is under great military pressure in its Pakistani strongholds. The message was heavy on US foreign policy but light on jihadist ideology, which many see as part a new strategy to win over mainstream Muslims. As al-Qaeda has become a more disparate organisation, Bin Laden has struggled to maintain political and spiritual unity. But he has survived nearly ten years of US warfare ostensibly directed around him, suggesting his spectre will haunt the world for some time to come.

9.Nouriel Roubini

Financial foreteller

Overoptimistic capitalists at the New York Times described him as "Dr Doom" back in 2006, but even they now agree that Nouriel Roubini predicted financial meltdown before anybody - yes, anybody - else. And, with a pessimism that governments the world over should be taking far more notice of, he continues to argue that the old financial systems must evolve, and that recovery from recession will be slow and painful. Less public intellectual than economic adviser to Planet Earth.

10. Xi Jinping

Chinese kingpin

Xi Jinping is increasingly seen as President Hu Jintao's likely successor. Considered open and pragmatic, Xi is tipped for promotion at the Communist Party plenum being held in Beijing. He has attracted praise from the former US treasury secretary Hank Paulson and Singapore's Lee Kuan Yew, who has suggested he is "in the Nelson Mandela class of persons".