dsgtc0408: Thanks for the clarifications! You've given me tons of valuable info. Now I just have to decide on whether/not to go to the zoo, but otherwise I think I'm set.
DeepUnderground: I will heed your advice, esp for short distances and also for getting to places where public transport is not convenient. One thing I'm worried about is catching taxi back from places. I'm reading that Singapore is not like HKG where cabs are easy to catch and hail-able anywhere. I read that they may be difficult to catch at certain places during certain hours, and also you generally have to go to a designated taxi stand or a hotel to catch one. Anyways, push comes to shove, we could always take a bus/train.