United States is the only official superpower, but I believe China and the European Union quality as a superpower.

If you are counting Unions then I would say definitely the European union,  dont know if I would agree with China though,  technologically they arent very advanced with their military, they only have alot of it.  And if that was the defining feature then Russia would have to be included as well I would think.  

Being a superpower isn't really something I consider a good thing.  It seems the US is the only superpower.  I'm totally against empires, though.

http://www.youtube.com/watch?v=UQBWGo7pef8

The United States is the only super power at this point in history. Whilst Europe may have a huge economy remember that its still a collection of lots of nations and some of them (notably club med) are weighing the union down with their eccessive debt (and plenty of people are now dumping the Euro in the short term because of this). Plus outside of the UK and France Europe doesn't reall have the military might to be considered a superpower (and those countries don't have enough power alone or collectively to be super powers).

In my mind you need both the economy and the military to qualify as a superpower. China may be growing rapidly but they cannot project their power around the world yet. So they don't qualify either.

Neither does India.

I'm not sure about Russias projection capabilities, but I know The United Kingdom has significant projection capacity but nowhere near whats required to be called a Super Power.

In the future however, China will become a superpower. They're already developing significant amounts of countermeasures to US dominance in their part of the ocean to deny and slow US access. If a war broke out tomorrow the US would prevail however. Of note is that even when China becomes ecenomically larger then the US it will still probably take a long time after that before it can overtake them militarily I think.

What China also lacks in comparison to the US and the UK is cultural power outside of its borders. The US and UK are huge cultural exporters that dominate the world with their culture, this is aided by the fact that both countries are democracies and thus get along very well with the other democracies in the rest of the world. Which is something that China will always lack in its current form. I think the US can probably rally more support amoung the most powerful countries in the world more easily because of that simply fact.

the vatican

Who made the united states the official super power? The league of super heroes? Maybe you are just using the word official informally but I don't think you can claim any country is "officially" a super power.

I completely agree with this. If anyone can claim to be a superpower, it's the Vatican. Nobody really knows how rich the they are and they hold the hearts of 33% of the world.

Its an interesting idea. Although no-one as you say really knows how much money they have. I'm assuming that the Vatican doesn't ever realease any of its financial data?

They don't like to share. Some estimates put them somewhere between extremely wealthy and sinfully wealthy, while others claim they are actually in need of funds. Short answer, nobody really knows.