Night photography presents challenges, but also offers opportunities to capture the world in a very unique way. To pull off longer exposures like these, a good sturdy tripod is required, as is a remote. Counter intuitively, the heavier the camera the easier it is to get sharp long exposure photos. Using the exact same tripod, I had significant problems with camera shake on my D5000 (very light) and have very few with the D700. The extra mass damps vibrations, like those caused by the mirror and shutter.
Long exposures capture motion, particularly of lights, in a magical way. Stationary lights, especially at high f-stops, produce star flares and long exposures allow beams of light through even thin mist or dust to burn in and show up in the image. Water becomes soft, silky and otherworldly.