A theory I heard recently is that Singapore's economic model is a combination of Hong Kong, Hawaii, Las Vegas and Monaco.
Hong Kong - Financial services (and probably having a lot of expatriates).
Hawaii - The locals in Hawaii all work in the service industry (tourism, there). They make a living, but they don't earn very much.
Las Vegas - Gambling. 'Nuff said (probably MICE also).
Monaco - Attracting high net-worth individuals.