Hong Kong, China

If cities were people, Hong Kong would be a rich Wall Street guy with sweat stains and an Asian fetish. Hong Kong has by far the highest population density in the world. Imagine if Manhattan was a gigantic hill and every building was twice as tall. Throw in some sky bridges and the longest escalator in the world and you end up with the most urban environment on the planet.
There are so many young western expats living in Hong Kong, you forget that you’re in Asia at times. The island has everything you could want back home — great restaurants and night clubs, big career opportunities, over-educated single 20-something women — while the mainland still delivers the cultural diversity (or insanity, depending on what you’re going for) that you come to expect from Southeast Asia. I could live here.