Singapore is a very photographable city; I find it really demands color film. I'm not aware of specific "must photograph" subjects, but it's a good place for just wandering around finding interesting compositions. (Best street food on earth, too.) Apart from the obligatory photos of the skyline and the Merlion, I find most of my good images from Singapore are small-scale things: my son playing in a neat-looking spot in Chinatown, a colorful pedestrian bridge in good lighting, a guy in a hazmat suit spraying DDT around the hotel, things like that.
The west coast of Malaysia has the best sunsets I've ever seen. I'm not normally one for calendar-pretty sunset photos, but *damn*.