I use the Nikon D90 and my 2 most used lens are the 17-55 2.8 and 70-300VR. I do have others but those are used most.
If you have a Nikon and want to get Nikon used lens or cameras go to the Nikonians.org. I have bought and sold there and the bargins are great and these people baby their equipment. I have learned alot there. For Alaska I bought the Sigma 150-500 and hope to get some good shots.