Take a camera, even at night. If you see some color, there is a photo to be had. Find a place to set the camera down, and you can have a sharp, low ISO exposure. You only need a few seconds, even with the lens stopped down. No flash was used in any of the photos below. They all were taken with a Nikon Coolpix A, a crop sensor point and shoot. For cityscapes, that's really all you need. Even if a person walks through your picture, they'll disappear with an exposure of more than a few seconds.
Gear Photos were shot with a Nikon Coolpix A.