Im from thestates but London would be a nice place to have it. It is beatiful and not like grimy looking like my birth-city(NY). Moscow would also be a neat place.
I think Australia should again, we did it before and that crazy guy said it was "The Best Olympics Ever" and you know its true because a crazy guy said it
New York is too urban. Moscow is too rural. Paris has nice sights, but government might be a problem. London has good sights too. But, I'm not sure about Madrid.