1) US
2) China
3) Japan
4) Russia
5) India
6) South Korea
7) Norway
8) Germany
9) France
10) UK
Quite a realistic list. I would actually move Norway up the rankings by 1 more.
US - Obvious.
China- As the second largest economy, the highest growth rate in capacity and a massive middle class; they have a reason to be the second strongest.
Japan- Even if their economy is declining, the political clout they have along with their economic clout is second to none. The only reason they are not second is because they do not have a permanent seat in the UNSC.
Russia- A seat in the UNSC, a major muclear power and enough diplomatic and economic clout to shut down Europe in a few days. Yeah! They have what it takes to make the list. With a more established economy and a modernized military they will move up the rankings.
India- A rising power and demands from other countries to head economic initiatives along with China and US, there is no reason why we shouldn't be right up there with the best. After all we now have a symbol for our currency.
South Korea - It is a regional power no matter how you look it and only behind US and Japan in Science and technology. As a major economic hub, it is as good as the Euro nations in socio-economic clout.
Norway - A major superpower when it comes to softpower. Nothing has influenced more in the modern world than the Nobel Peace Prize has. It is also a major country in setting up peace initiatives, weapons curbs and peace deals. It is a model country for the world to look up to. It has a major voice in the World Bank as well.
Germany, France and UK- The biggest euro economy and 2 major military and economic powers with UNSC seats. Nothing needs to be told about them.