most of us will have to use the finest lenses, and have near impeccable technique to draw forth the best image quality capture at source in order to fully get the most out of all those 36 million pixels on the d800. not to mention that the light has to be reasonably good too to make our subjects look great, whatever they may be.
i presently shoot a hasselblad h4d system for my medium format work, and almost invested in a Leica S2 with more lenses for "better image quality." what i saw from controlled testing did knock the socks off my feet. whatever nikon did to this sensor, it is possibly one of the best sensors of all time.
reference link here for those interested:
diglloyd.com blog - Readers Comment on my Nikon D800 vs Leica S2 Shootout
the d800 and the E variant it seems, will technologically revolutionize photography as its image quality capture trickles down into the rest of the consumer market. whatever Nikon did, they took the outstanding dynamic range, color fidelity and anchored black tones of the D3X, and paired it with the noise suppression and detail retention of the D3S (i have owned the D3X for 3+ years, and the D3S for 2+ years) and packed even more pixels in to make it the ultimate all around digital SLR.
the way i see it, the majority of nikon glass will not be able to keep up with the demands of the sensor. we'll be diffraction limited at one end - and yet not able to optimize image quality at maximum aperture (unlike the Leica-M glass). autofocus will have to give way to live view on a tripod for the most reliable and consistent AF. its a different animal altogether. In case anyone thinks I'm knocking on Canon, I've shot canon for 7+ years now, since the original 1D and 1Ds and all the way to the 5D2 and 1D4 and have a veritable amount of L glass as well.
for best results, I am inclined to agree - you need to invest in top tier Zeiss/Leica-R adapted glass, shoot off a sturdy tripod, use the live view and focus with absolute precision. pretty much anything less than excellent technique and lens will yield suboptimal results.

I am thinking of trading in my D3S in exchange for a D800E in the future (since all my primary shooting systems have no AA filters on the sensor) and was also taken aback at how high ISO shots on the D800 when downsampled to native D3S resolution - looked... like D3S files.
This camera is a game changer. It just cut off the bottom third of the medium format digital market overnight and reduced the price point for such image quality by a factor of eight.