Raffles and the Singapore Sling are not my top draws to Singapore, but they do a good job of capturing the spirit of the city. In my opinion, Singapore is all about the food; Chinese, Malay, Indian, fusion - it's all there. The best food in Asia, in my opinion - all presented against the lights of the Quays at night, the smells of Little Indian, and the world famous hawker centers (which are really just outdoor food stalls pulled inside by the Singapore government for cleanliness and oversight purposes).
I recently spent a week in the city. A week that was highlighted by consuming 6 whole fish and 3 crabs washed down with a variety of beer, martinis, and (of course) the Singapore Sling.