I'd say that depends on your intended use. If you're into landscapes, general snapshots, architectural stuff, etc. which don't generally require fast action shooting situations with moving subjects and fast focusing like sports photography or action nature stuff go with the cheaper one. If you are going to ask the camera to focus quickly, especially in low-light situations on fast moving subjects, you'll want the one with the best fastest autofocusing motor you can afford and big, heavy, fast lenses that let in lots of light. I am currently shooting the N-80, D-70s and D-200 and sometimes borrow a buddie's D2X with a variety of lenses and love them all. Any of the ones you mentioned are great cameras.
The lenses themselves don't have their own power source (still use battery power coming from your camera body to power the focusing mechanism), but some of the better ones do have camera-body-powered focusing motors inside the lens to help move those larger lens parts and make them focus faster and/or quieter. Nikon calls this SWM or silent wave motor. Basically the lens focuses faster and quieter with it. With Nikon lenses if you see "ED" or "Nikkor" it generally means good glass, if you see "AF-S" it generally means the lens has a motor in it so it should focus faster and quieter than a comparable lens without one.
But again, unless you're using it to stop action, the faster focusing is not needed. Nothing in a landscape is gonna "get away" before you can focus on it. So no need to have fast body/lens for that, just get good glass so the images are sharp and free of chromatic abberation. Having owned several different camera bodies from Nikon I think the single biggest difference between each (for my uses-fast action nature) is the focusing motor in the camera body itself. Yeah AF-S lenses are faster. But the same AF-S lens on a D-70 focuses slower than it does on a D2x. The better ones perform better, faster, truer with all of my lenses, and the slower ones make my fast 2.8 lenses seem a little slow because the motor in the camera is a limiting factor. There... more than you ever wanted to know when you posted this thread. :Wow1: