Megapixels

I have always said that a 3MP camera will do just great for most people, because they really only want to print a 4″x6″ print, if they do any prints at all.  But for those that want to print an 8″x10″ print, then you will want 7.2MP.  The rule of thumb for a realistic photo-like print is 300dpi (e.g.  4*300 x 6×300 = 1200 x 1800 = 2.16MP), which is why 3MP is more than adequate for printing a 4″x6″.  The more important factor is the quality of the lens and the CCD in the camera, which help get you realistic colors and a sharp, focused image.

See this article by Ken Rockwell for more information on the megapixel myth.