I prefer my D40 to my heavier cameras because I prefer the rear-LCD only display over my older cameras’ film-era split displays on the top and back of the camera. Why should I move my head to look two places when I can have it all right in front of me on my D40? My D40 has about double the battery life of my D200, so I never need to buy or carry a spare battery, even to make 750 shots in a day or more.
Its light weight, super-close focus and unusually good zoom ring make it a joy to carry and use. I can zoom precisely with one finger, compared to the$1, 100 Canon 24-105m IS which requires two fingers, and is difficult to zoom precisely at the wide end.