and I can not tell if it's been used or not. It DID come in the plain brown box marked "Certified Reconditioned Product". As I never purchased reconditioned before, I don't know how they typically come packaged. All of the transparent masking film was still on it; on the display screen, the bottom of the foot, even on the Apple logo on the back. There is not a smudge or fingerprint on it, but I'm sure they are able to clean them as good as "factory fresh". The keyboard and mouse cords are still kinked from being folded up, and everything has all the plastic sleeves and wrappers on them. There is no dust ANYwhere, and not a single wear spot on the glides on the bottom of the keyboard or mouse. It smells new.

All-in-all, I do believe it's unused.
It also came with an iLife '09 disk, which is an added bonus. I was expecting just iLife '08 pre-installed, not a free upgrade to '09.
Right now I'm downloading all of the Apple updates, including Leopard 10.5.6
I just looked at the keyboard again - the little glides on the bottom have already gotten slight discoloration on them just by sitting on my desk and moving the keyboard around. And the white plastic on the underside of the keyboard is already picking up dust. I really do believe that it's unused, but unless anyone knows of a way to prove that I'm just going by my observations.
Heck of a deal! I may not ever buy another new Apple computer again!