It is a little confusing, but Apple is selling 2 different i5 chips. The one available in the 21.5 inch iMac is a 3.6MHz dual core, while the one in the 27 inch iMac is a 2.8MHz quad core. I'm not interested in the 27 inch (too big), so it's either the standard i3 (3.06 or 3.2) or the upgraded i5 (3.6MHz). Anyone have an opinion on whether the $200 upgrade (13 to i5) on the 21.5 iMac is worth it?