The full frame sensor, the noise reduction capability, the sensor quality etc really sets D3 apart from no-professional cameras. Yes, it demands a high (too high for many of us), but for that the performance are stagerring. I have read reports and seen results of photographs taken with D3 during an opera (extremely low lighting condition) - with ISO25600 - noise is unavoidable but it is quite accetable. It is possible for us to take digital photographs at low light with given light - hand held! I have stretched my Canon40D to the limit - ISO800 but beyond that I am really not happy with the results.
Horses for courses - D3 is for those with deep pockets, or for the pro that relies on their equipment to earn a living.
I have handled the D3 on one occasion and I must say I like the feel of quality - overall feel all the way down to the high resolution LCD screen.