Donīt know, if the information provided here is new for everybody, but I think it is worth a closer look:
http://6mpixel.org/en/
Steve
Fascinating. Thanks, Steve. Useful information.
Robert / Seattle
This is only relavent to compact cameras, DSLRs have much bigger sensors, and have single pixel sizes bigger than the optimum size(3 microns) mentioned in this article, the new EOS 1Ds MkIII is 21.4Mp and has pixels that measure 6.2 microns.