I currently have a 24" Alum iMac 2.4 C2D with 4GB of RAM. Looking at the new lineup and ignoring the i7 model. Which would offer the best speed increase out of the box compared to my 2.4? the 3Ghz C2D 27" or the 2.66 core i5 27"? I know the 2.6 is QUAD but in real world usage, does anything really jump using that machine? Or is it all marketing with little increase in speed? On paper, 2.4 to 2.6 isnt justifiable to spend $1999, whereas 2.4 to 3.06 is for $1699 (on paper of course) Let me know what you think?