Interesting that you should put Germany on 'our' side. In all the previous world wars...
Here's what I've come up with:
Most muslim countries, in the middle East and Northern Africa, join together to war against the infidels. (Especially the USA and Europe. Possibly Russia could be one of their targets as well.)
On the defensive are, of course, the countries being attacked. In addition, I would expect at least token help from many NATO members, and if Russia was attacked, perhaps members of the old Soviet bloc (perhaps even Red China?) India might join in just for the opportunity to attack Pakistan.
Most of the Orient and South America would attempt to stay neutral.
This would be a messy war, with lots of losses on both sides, and only the slightest lip service paid to the rules of warfare. At first, the Muslim nations would do well, but once the other side stopped trying to pacify, and started trying to conquer or destroy, it would go badly for them, especially if they had the impertinence to attack Russia. In the event that the Muslim countries managed to almost defeat one of the allies, the war might go nuclear.
The emerging superpowers of China and India, as well as a number of other third-world countries tired of the current economic system, band together, and set out to destroy those that have taken advantage of them for so long.
The other side of this one would be mainly the USA, but likely with help from Canada and European countries, perhaps with token help from South America as well.
It would be interesting to see which side Japan took in this. I would expect them to side with America and Europe, except that they are so very close to China: they wouldn't want to be the front lines. Possibly they would force the USA to give up its Japanese bases and then declare Japan neutral.
This would be a horrible war, with enormous casualties on both sides, though I think this one would be less likely to go nuclear, as both sides would have their own arsenals. With numbers against technology, the Indio-China axis would take extreme military losses, but would have plenty of replacements. The allied powers, however, would take heavy civilian losses as their enemies targeted economic centers, especially at first, while they are surprised.
Thankfully, this scenario doesn't seem likely, because the countries on the Indio-China axis would realize that if they destroyed their 'oppressors' they would wipe out their own economies as well, which depend on selling things to the enemy.
And where do you set all the other European countries?
Germany would just stay with the other European countries. We are more like a close group...
war is a bad thing wish that it would never happen
All there theories sound interesting but they are not going to happen.. there will be local wars only and if they spread, the use of nuclear arsenals will not be possibly prevented, thus ending the age of mankind.