2009 is probably OK for the historic landmarks (unless they have been closed down), but a lot of new major landmarks have opened, like
Marina Bay Sands, which includes a lot of amazing book well in advance restaurants like Waku Ghin,
Resorts World Sentosa which includes Universal Singapore. If heights aren't a problem the Sands SkyPark will give you an amazing view (57 floors up)
http://www.yoursingapore.com/ is probably a good place to check for up to the minute ideas, and their online guide book, where you make your own guide up according to your interests can be printed out.
One thing to remember is Singapore is bascially hot all year, the main weather variation is the humidity level, afternoon storms are common in the wet season, you could almost set your watch by the storm clouds rolling in and dumping rain, then rolling on. What looks like an easy walk usually isn't due to the heat and/or humidity. Use the taxi cabs, they are pretty cheap. The MRT train system is very easy to use and very cheap, but it's mainly underground so you don't see much while you are using it, and you will almost always come out of the underground train station on the wrong side of where you thought you would be, delightful as exploring by accident can be, with your limited time, probably not the best use of your time. Buses/taxi's you see a lot more and you know which side you are on.
