Originally posted by Sandwich
To be blunt, a "World Capital" not only doesn't make sense, but can't realistically work while there are seperate nations on the planet.
Not necessarily. Organizations like the EU have a capital city (whether or not its called that). As the world moves towards a centralized government, it's likely to be a gradual transition. Sure, at some point in the future nations will probably disappear, but there's no guaratnee that this will be before the time comes to choose a capital.
Even in a completely centralized global government, there will likely be pseudo-nations ("administrative areas"), simply because of beaurocratic and logistical reaons. Think of the individual States within the US. Or even think of the UN, where all the members submit to a central authority on certain matters, but retain a degree of independece. Right now, the "world capital" could be said to be New York, because that's where the largest, most powerful and only legitimate international government in stationed.