Lately there have been many posts from newbies asking about the differences between D40, D60, and D80.
Perhaps I should summarize what I know into point form below:
1) About 2 years old (2006 model).
2) 6 megapixel CCD sensor.
3) Smallest and lightest Nikon DSLR body.
4) Kit lens is AF-S DX 18-55mm f3.5-5.6
5) Camera body has no in-built focusing motor. Hence, in order to have auto-focus function, you need to use a lens which has an in-built focusing motor, e.g. Nikon's AF-S and AF-I lens range.
6) With other lenses (eg. AF), all other functions are possible EXCEPT auto-focus. You can still focus manually. A green dot appears in viewfinder when subject is in focus.
7) All past and present Nikon (or Nikkor) lenses can be fixed onto this camera (and all Nikon cameras) and be used to take photos. Nikon's lens mount has not changed in decades.
1) 2008 model.
2) 10 megapixel CCD sensor (same as D40X and D80 (i think) ).
3) Image sensor cleaning system.
4) LCD auto switch off when eye is looking through viewfinder.
5) Same size as D40 (smallest and lightest).
6) Same issues as D40 with lenses. Can only auto-focus with AF-S and AF-I lenses. However, the 'rangefiner' display makes manual focusing quite easy and quick.
7) Kit lenses are updated from D40/D40X. Include VR (Vibration Reduction) function.
1) 2006 model.
2) 10 megapixel CCD sensor.
3) Larger and heavier than D40/D60. Body has more magnesium alloy components. Feels a bit more solid to hold and operate.
4) Kit lens has larger zoom range (18-135mm f3.5-5.6).
5) Can meter and auto-focus with AF, AF-S, AF-I lenses. Has mechanical drive pin.
6) More functions (image quality, ISO, WB) can be quickly accessed via rear buttons, without having to dive into the menus. Allows quicker setting changes.
7) Additional LCD screen on top of camera, and secondary command dial near index finger position. Allows quicker setting changes.
8) For those interested in studio photography with multiple flash guns, the D80 can be programmed as a remote commander for Nikon Speedlights SB600 and SB800.
9) Additional purchase of Nikon authorised battery grip MB-d80 allows easy shooting in vertical (portrait) position.
10) Viewfinder is pentaprism (instead of pentamirror in D40/D60). Generally agreed that it is bigger and brighter. Makes framing slightly less strenuous.
Hopefully this answers most of the basic questions that newbies want to ask about these 3 cameras. If anybody has anything to add, please let me know.