You'll find that a lens can quickly exceed the cost of the body. Different lens are designed for different applications, then there are those that try to be all things to all users.

The kit lens is a good example of the "all things" theory. It will take a fair close-up, and a fair zoom, but doesn't do anything exceptionally.

You can't lose with a prime lens (one that is a fixed focal length) as they are usually much sharper with a wider aperture for the money than than zoom lens.

A great lens is the Nikon 50mm f/1.8 (nifty 50) which runs a $100. Another lens I really like is the 35mm DX prime (about $200). Both lens are very sharp and force you to pay attention to your composition, (more so than with a zoom anyway).