Did you take a look at the other camera photo samples, I'm sure that all or most of the sample shots on the Nikon site are from their top lenses. I've not checked myself but I'm sure the D90 and D700 (which I've owned) have sample shots with their lenses of 2.8 or wider.
It seems like normal marketing to show images for the D800 with Nikon's best lenses. I plan to use the following lenses with my new D800....... Nikkor 16-35vr F4, Nikkor 24-120vr F4, Nikkor 50mm 1.8D, Nikkor 85mm 1.8D, Sigma 150mm 2.8 macro and Nikkor 300mm AF-S F4. I also have a nikkor 28-200 and 28-80 which I plan to try out.