One of the best things I love about Nikon D90 is it delivers great night photos even without using a tripod. Having an amazing DSLR equipped with Vibration Reduction (VR) lens make this kind of shooting possible. It allows handheld shooting at twilight, at night and even in poorly lit environment. Although nothing beats a tripod, I don't usually carry one when I travel as it's heavy to lug around all the time and it takes too much time to set up and take down.
Here are some of my best handheld shots of Singapore captured from the observation deck of the Sands Skypark. Enjoy.