Hello friend I review this according to my experence .
specification of nikon D40
6 megapixel DX format CCD(1.5x FOV crop, as D50)
Nikon Image processing engine(as D80 / D200)
3D Color Matrix Metering II, 420 pixel sensor(as D80 / D50)
New Multi-CAM530 three area AF sensor
ISO sensitivity range 200 - 1600 plus HI 1(3200 equiv.)
Custom Auto ISO(selectable maximum ISO, minimum shutter speed)
2.5 fps continuous shooting(as D50), unlimited in JPEG
No status LCD, new LCD monitor based status / settings screens
Help suggestions on LCD monitor(eg. scene too dark, try using flash)
Large 2.5" 230, 000 pixel LCD monitor
Bigger viewfinder view(x0.8 magnification, 95% coverage)
Short shutter lag and viewfinder blackout
Support for SDHC(SD cards over 2 GB in capacity)
In-camera retouching
D-Lighting(shadow / highlight enhancement)
THANK YOU