I'm going to SIN for four days in Dec (18-21) for a vacation/MR and have found enough stuff on-line to do that well lets just say I'm probably going to need to go back again next year. I can always use the miles

In order to make the most of my time over there what would you put on your list of things not to miss?

I couple of things I have on my to do list are:

Night Safari
A half day tour of spice gardens, wet market, Little India, Chinatown.
A full day tour that takes me to some of the sites outside the city such as Tiger Balms Garden and Ming Village
Cable car to Sentosa
A day tour to Kukup and Orchid Valley in Malaysia
General tour of the city