The Nikon D3 is on my wish list.
I currently have a Canon 20D. It's OK. But it is hopeless in the dark - early evening, churches etc.....
I have done some shooting with a D3, thanks very much to Stephen Walker. It is wonderful! Heavy - especially with good lenses on it - my arm is aching after a few hours holding it. I found the focus a bit difficult to get used to - either the single frame - wait for the beep! or the continuous which I am sure if fantastic for sports photography, but for weddings and portraiture..... When you have a few guys in the frame, you focus on the closest, re-compose and shoot and then find out that it has re-focused on you to the person in the middle or back.... Fun and games!!!!!!!!
Anyway, this is my wish item at present.