I'm really into night photography, which is an area of photography that has it's own little cult following. If getting good night shots is really important to you, then here are some recommendations:
-Get the fastest lens you can afford. In lens terminology, how "fast" a lens is depends on how much its aperture will open. The smaller the f-stop number, the larger the aperture. For your camera, you can get a 50mm f 1.8 lens for about $140 or less. Or you can get a 50mm f 1.4 lens for about $375 or less. Using a camera with the lens aperture at the widest setting is one variable in allowing you to shoot at night. What you sacrifice when using a wide aperture is depth of field. That means that if you are using a wide aperture and you focus on your subject, then things in front of and behind that subject will likely be out of focus. However, with night shooting, you're generally taking pictures of structures that are lit up. And most of the time, depth of field isn't even an issue in these situations.
-The next consideration is the shutter speed. The slower the shutter speed, the more light will get to your image sensor, and thus, better capability to shoot at night. The trade-off here is that if you are hand-holding your camera, then you will likely have some motion blur at slower shutter speeds (unless you are someone who is just really good and holding your camera perfectly still). For the average photographer, you will get at least some motion blur if you are hand-holding your camera at a shutter speed of any slower than about 1/25 of a second. The wider open your aperture is, the faster your shutter speed can be.
-Something that helps a little bit with motion blur is if you get a lens that has image stabilization (IS). You'll note that pretty much everything in photography has a trade-off, so it boils down to personal choice. The trade-off when using image stabilization is that it uses more battery power on your camera. It also is a technology that really hasn't quite reached any level of "wow" factor yet, so in other words, using image stabilization usually doesn't make a significant difference...but every little bit helps.
-Even if you aren't super serious about getting great night shots, a tripod is still almost a necessity for this type of photography. If you don't want to get a tripod, then there are other workarounds (i.e. anchoring your camera on top of trash cans or other stable objects), but you're still very limited. I'd recommend looking into getting a small lightweight tripod. One caveat: I've read that the Disney parks are cracking down on allowing guests to bring tripods into the parks, so you may want to look into that before buying one. Another thing you might want to consider is something called a "gorillapod" by a company called Joby. They are a little pricey, but they are compact and very versatile. Unlike a traditional tripod, the legs on a gorillapod are flexible and can be wrapped around things like light poles, etc.
-The next thing would be the ISO setting on your camera. You probably know this already, but the higher the ISO number, the more sensitive your camera is to light. As usual, there's a trade-off however. The trade-off here is that the higher the ISO number, the more digital "noise" you're going to have. "Noise" is all the grainy little colored speckles that you see in digital pictures sometimes. High ISO settings, and very slow shutter speeds (like 30 seconds or more) are the two things that will cause noise. On a typical digital camera, you start to notice a little bit of noise at around ISO 400, and then when you get up to about 1600, it will be a lot more noticeable.
-Shooting in RAW is highly recommended for night photography. This is because with RAW images, you have a lot more versatility in image editing software (such as Adobe Photoshop). You can do things like increase the exposure after the fact, and also reduce noise to some degree.
-One big mistake that a lot of people make with night photography is the use of flash. Generally speaking, to get the types of shots that have likely impressed you on this site, you won't be using a flash at all. In particular, the camera's built-in flash is pretty much useless. Occasionally, I will use an external flash for night photography, but what I'm using it for is to "paint" the subject. This means that I'll put my camera on a tripod, keep the shutter open for several seconds, and then fire my external flash at different parts of the subject...so that that in the end result, the subject is fully illuminated. What a lot of people do, though, is they'll be taking pictures of things like fireworks and they'll be using their camera flash. Or they will be taking a picture of, say, Space Mountain from hundreds of feet away, and they'll think the little built-in flash on their camera is going to illuminate the entire structure. Unfortunately, it doesn't work that way.
One more thing... Your camera (the D70) should have a little bit of an advantage over some newer cameras as far as night photography is concerned. The D70 is a 6 megapixel camera, which is the perfect resolution for most pictures. But resolution aside, it should be more sensitive to low light than many cameras that have more megapixels. That's because as camera manufacturers try to squeeze more and more pixels onto the same size image sensor, those pixels have to get smaller, which means that each individual pixel is collecting less light. A lot of people are under the misconception that the more megapixels a camera has, the better the pictures are going to be. Megapixels have reached the point, though, where they've become more of a marketing thing (unless your goal is to do a lot of major cropping and/or enlarge your pictures to poster size).
Sorry for the lengthy response, but hopefully this gives you some useful information.
