Upload & Sell: Off
It is not a different world, it's a different planet...
I am surprised that people compare models from completely different markets. There is a huge difference between D80 and D200, so I can only imagine the gap between D40. Recently, I upgraded from D80 to D200 and there is no question in my mind, which camera is better. "Same sensor", "same autofocus"... The difference is how it is applied in the camera. D200 has much better metering system, far better AWB and I will not go into the obvious - handling,durability, build quality etc.
The question that remains is: do you really need D200 if you doubt that if may not be very different to the D40.