Yoshi,
I upgraded from the D40 just before Christmas. I've not looked back.
Lots more focus points to choose from, a far far superior ISO performance and for me one of the best things is the ease of use. The main settings I use can all be accessed on the body rather than fiddling in the menu system. I find the display on the top of the camera very handy also.
I loved my D40, but the D90 is different class in my opinion, you'll not regret buying one at all.
I upgraded from the D40 just before Christmas. I've not looked back.
Lots more focus points to choose from, a far far superior ISO performance and for me one of the best things is the ease of use. The main settings I use can all be accessed on the body rather than fiddling in the menu system. I find the display on the top of the camera very handy also.
I loved my D40, but the D90 is different class in my opinion, you'll not regret buying one at all.