I traveled in Singapore on the 2d and 3d of march 2006 which is only two days.
This is the second stop of my Asian trip which include in chronological order India, Singapore, Malaysia and Brunei, Thailand, Laos, Vietnam and Cambodia.
I visited the following areas: center city, Little India, Chinatown, Sentosa Island, Ang Mo Kio and Orchard Road.
Many people think Singapore is just an expensive city where there is not much to do. That wrong ! Singapore is a very interesting place and very pleasant remember me of Sydney. In addition you can find a bend in a bunk for a reasonable price and food and transportation are rather cheap.
Obviously this country is much more expensive than other South-East Asian countries but is also more modern and rich.
About transportation, the best is to use the MRT (a ultra modern subway) and buses.
You can get an Ez-Link cart for 15S$ (5 S$ for the cart which are paid back when you return it and 10S$ for transportation). This electronic cart allows you to get on any bus and subway of the city.
I slept in Hotel McKenzie (12 S$ include breakfast).
A meal in one of the numerous food center cost between 2,5 et 8 $S.
In two days I spent 100 S$. I don't include the new battery for my laptop and the new memory cart for my camera I bought.
Speaking about that you still can find electronic products for a good price. The best place to go at the time of my stay was Sim Lim Square, located in Little India.
My opinion about Singapore: a very pleasant city with many things to do and many places to see. So If you had the idea to go there only to get an other plane think twice ! Two days is a bit short, better stay three if you can.