Some of my picks for future host cities (SOG or WOG)
Asia:
Tokyo
Delhi
Kuala Lumpur
Seoul
Europe:
Andorra la Vella (made an official bid for the 2010 WOG, but lost)
London
Paris
Berlin
Istanbul
Rome
Madrid
Oceania:
Sydney
Brisbane
Melbourne
North America:
New York City
Denver
Seattle
Toronto
San Diego
Miami
Mexico City
South America:
Rio de Janeiro
Brasilia
Sao Paulo
Buenos Aires
Montevideo
Africa:
Cape Town
Johannesburg
Alexandria
Cairo