4. New York CityThe most populous city in the United States and the center of the New York Metropolitan Area. With a reputation as the city that never sleeps and some of the world's best bars, cocktail lounges and nightclubs, it would be hard to beat the Big Apple in the nightlife stakes. Hotspots for wining and dining include Lower Manhattan and Soho, with the Meat Packing District a buzzing nightlife hub.