Here's the menu that really sets the Nikon D40 apart from all the other entry-level DSLRs out there. You can really do quite a few useful image manipulations right on the camera, no computer needed.

Some of them seem a little gimmicky, in our thinking (Image Overlay, for instance), but the color filtration and D-Lighting options are genuinely useful.

Missing from the D40's Retouch menu are some color-filtration options when c converting from color to black-and-white.

In the D80's retouch menu, you can apply color filters when converting to black/white, the D40 offers only a default conversion.