Australia... no, seriously. If we play our cards right, we might get something close to Great Power status.
As for "superpowers", I think if the United States loses its position there wouldn't be one for a long time; it will be a multipolar rather than a unipolar or bipolar world. China won't grow so powerful as to dominate the world politically, economically or culturally as the United States had, and the United States would still be quite influential even if it's no longer a superpower.
The European Union needs to decide what it really stands for.
Russia's superpower days are well and truly over; it might still be able to secure a spot among the Great Powers for the next few decades yet though, especially if United States and the European Union continues to do badly economically.
Some other countries to watch out for: the Southeast Asian countries, particularly Indonesia and Vietnam, Egypt, Iran, Korea, and Turkey if it sorts itself out.
I agree.
As United States is a hyperpower, China will not, and doesn't want to (fear of the responsiblities in the whole world's affairs, please refer to US if you are not sure enough), become a hyperpower, finding herself as a normal superpower will be more decent, fit and appropriate.
United States will constantly decline, in a stable and slow pace. The speed will be slightly slower than other countries expected, but faster than most Americans expected. A stable decline will be good for the whole world.
The above 2 paragraphs are some objective findings from the book, Day of Empire ..How Hyperpowers Rise to Global Dominance--and Why They Fall, and some of my views, please refer to the book if you want futher infomation.
In my opinion, I think that the European Union may have great potential energy if they have successfully unify Europe (at least West and Central Europe), though it is possible that coming to an end.
The Russians will no longer a major power in the late of the ceuntry, but it simply does better than any one of the European countries, especially when comparing one by one (except France and Germany, but I am not certain).
Iran, Turkey and Indonesia might be main participants of world affairs in the next ceuntry. The world will be in process of federating. Superpower countries will not be as influential as before.