Noise Reduction

[Big Mike]

I'm just playing devil's advocate

The OP was talking about selling prints on various websites...which leads me to think of landscape/stock photography, rather than assignment photography.

 

[KmH]

Actually the D3X isn't that great a high ISO performer. It was optimized to be a studio camera and use slow shutter speeds.

The best DSLR on the market today for high ISO performance is the just released D3s, optimized for shooting sports at night and getting as much shutter speed as possible.