This is very interesting, it appears that Apple are using a panel which has 98% less of the colour spectrum that the previous generation had.
http://www.theregister.co.uk/2008/04/01/apple_imac_class_action/
"Indeed, the new 24-inch iMacs display 16,777,216 colors on 8-bit, in-plane switching (IPS) screens, as did the previous generation of 20-inch iMacs. But the new 20-inch iMac monitors do not even come close, displaying 98% fewer colors (262,144)."
http://www.theregister.co.uk/2008/04/01/apple_imac_class_action/
"Indeed, the new 24-inch iMacs display 16,777,216 colors on 8-bit, in-plane switching (IPS) screens, as did the previous generation of 20-inch iMacs. But the new 20-inch iMac monitors do not even come close, displaying 98% fewer colors (262,144)."