I was just in singapore.Singapore itself is the cleanest place you will ever go in the world, by a landslide. There is no gum or cigarette buds on the streets and the main part (most likely where the schools are) is very very developed (all new modern buildings)
However, i would not recommend going there as an American. Most habits that are common to american culture are highly frowned upon there and illegel. For example, it is illegal to talk about politics, sex, or religion. You will be arrested if you are heard talking about this. It is illegal to chew gum. Drinking is frowned up and thus, alcohol is VERY expensive. Talking loudly is also highly frowned upon
If you get caught with half a joint (marijuana for you kids who are sheltered), you get hung...no questions asked.
If the above habits dont sound like you, than by all means look into Singapore, it is beautiful, modern, and easily a first class country (TONS of money)