Optical zoom is a function of the lens, which can be enhanced by ISO capability. If you are looking at taking fast action in low light then you will need a fast zoom (f/2.8). There is no "do it all" lens. A nice system could include a wide to normal zoom, a short telephoto to telephoto, and a normal prime (50 f/1.8 for full or 35 f/2.0 for crop). If your budget allows, a full frame camera will let you snap at much higher ISO with much less noise than either of these cameras.
For macro you are in the same boat. The quality of macro photography will be dependant on the lens more than the camera body. I am more familiar with Canon, but Nikon and Canon are direct competitors and will offer very similar equipment at similar prices. For a preferable low light system be prepared to spend $$$ for nice lenses and/or lighting systems.
