I'll second the comment about the D90 being a great camera. I'll be interested to hear how much of an upgrade the D7000 is, as I'm quite happy with the D90.
A "body only" camera should include all the items originally sold with the body (such as battery, charger, strap, cables, user manual) but you should verify that. To use the camera, you would need, at a minimum, a Nikon compatible lens and a memory card. Memory cards are cheap. Lenses come in all price ranges--the advantage of a DSLR is that you can change lenses...but the more and better lenses you buy, the more you spend. A tripod is also a good idea if you are doing landscape photography. And you might want some filters. And an external flash. And a bag to carry everything.... Buying a DSLR is like taking the first step on the path of a dangerous addiction...you just keep buying more and more.
