So I'm an architecture student and I'm going to buy a new iMac as soon as apple announces the release date for snow leopard, so hopefully late this month. I've already decided to buy a 24", but I'm wondering if I should buy the 2.66 gHz or the 2.93 gHz one. I don't know if it will make a difference in 3d modeling programs like revit & sketchup or even illustrator & indesign. because aside from just the processor speed, the only other difference is the graphics card. is it really a $300 difference?