Once upon a time there was the simplest camera ever - Samsung Digimax S700 with a broken LCD and no viewfinder.
Broken LCD means that no options could be set (white balance, ISO, resolution, shutter speed etc) unless the camera was connected to a TV. Broken LCD also means that batteries could last a long time.
This camera was operated with sound not sight, and so it was perfect for mother-in-laws who usually have great hearing. Changing the zoom required putting the camera against the ear to listen how far to zoom, and to check if the camera was not in macro mode by mistake required half-pressing the shutter button to hear if the lens motor makes a long sound for macro or a short sound for no macro.
Believe it or not I used this camera for almost one year and I loved it! I took over 25000 pictures with it. Most of them were bad (blurred, heads cut, out of focus), but there were a few good ones in there sometimes. Example:
http://www.flickr.com/photos/alex_st...7594526775470/ (ok maybe that is not really a good picture).
My point is: any camera is good, and any camera is as simple as you want it to be. Any camera can take pictures by pointing and pushing a button. You can buy the most expensive DSLR and use it in Auto mode, and that is a simple camera. The rest (RAW, F-stops, white balance, face detection etc) is just extra technology which can be ignored by the mother-in-law who just wants a simple camera.