Light trail photography is relatively easy to do, and can produce professional-quality images of night scenes that most travelers don't even bother to shoot. And with today's digital cameras and their all-but-unlimited storage space, it's worth firing off a few dozen frames until you figure out your own low-light sweet spot.
I'm far from an expert photographer, but I've used this technique for years to shoot the interiors of bars and restaurants for freelance stories with pretty good results. If you've got a point-and-shoot camera like mine, switch it to the "night shot" setting, or simply turn off the flash.
Since the shutter has to stay open a long time to absorb enough light for an image, the camera needs to be perfectly still to avoid blurring. One solution is to use a small tripod (I have a Pod camera platform that I like), but if you don't feel like lugging one around, you can improvise. I've balanced my camera on tables, windowsills, door frames, bars, and even the rim of a pint glass - anything that can keep the camera still for the five or so seconds it takes to capture an image.
Since there's no flash, you can be incognito as you shoot, capturing candid moments and natural expressions. And the best part is that you never know how it's going turn out until you look at it. I was pleasantly surprised, for example, at how well this photo of Cafe en Seine restaurant in Dublin captured the dark scene.
If you've got a fancy DSLR, you probably know all the tricks already and can create images like these masterpieces, but whatever hardware you use, practice makes perfect, so kill the flash and start capturing the night.