Considering a new Nikon

[photogincollege]

Im pretty sure the d300 isnt full frame sensor, the d3 is, but i dont think the d300 is.

 

[itoncool]

D300 is not Full Frame, it's still using DX format sensor (1.5 crops). D3 is Full Frame.
D80 should be fine. It has the same image sensor with D200. D200 has better build, faster fps (frame per-second).

Object image are coming through the lens and captured by the image sensor, it creates picture. Sensor is playing the biggest role in a camera to determine the pictures, so the rest are just "additional accessories" that could help you in capturing pictures, but only if you need them, If you don't need faster fps then it useless, if you don't need more rugged body then it won't make any difference.
I own D200, a camera with many good "additional accessories", and I love it.