I plan to take the D300 and D800 only and perhaps want to swap lenses to see the differences. The 2 year old D90 I bought for my son has less than 200 images and frankly I know very little about its control so will be a learning curve for me as well.
For the lenses would be the 18-250 tamron, Nikon trio 14-24, 24-70, and 70-200 mm. All in a roller. I have been satisfied with my D300S' pictures so if the D800 pictures are not much better I need more practicing. My wife's point and shoot will also be a backup