A good beginner cam if budget allow is D90 kit. else the lower end D60 or D5000 and now D3000. personaly i will got for D90, cos its got a better grip and feel and the controls are better.
the kit offer a good reach in terms of focal length and the camera can use all type of nikon lenses and in terms of hardware performance , the D90 is pretty good.
once u have gotten used to the camera and understands the effects of aperture, shutter speed, ISO and WB. then its time to move onto better equipment AKA the lenses.
u will only learn to appreciate constant 'F' lenses after u understand aperture. and will also learn to appreciate prime and their big aperture, and see the different in in using different aperture to give u different DOF
after knowing how to appreciate lenses and what they can do for you, u can then look further in getting a camera body that suit your needs. maybe its the 1st DSLR u been using till now or a newer better body.
jumping 1 shot to the best is costly and might not be your cup of tea in the end, but it save your $$ if photography is really your cup of tea. another $$ saving method is to do research and understand what u want or need and buy the correct equipment, but this can be done only if u understand the limits of your equipment and what u will want and the market can offer.