NOT taking into consideration cost, which upgrade (from 5400->7200RPM or 2.4 i5--> 2.66 i7) would have a more significant effect on usage for a Macbook Pro 15? If there would be different strengths and weaknesses, i'd appreciate the subtleties, as well. I know this is an odd configuration question, but it's because i'm choosing between a custom-configured 2.4 i5 MBP w/ 7200rpm 500GB HD vs an eBay-listed 2.66 i7 MBP w/ 5400rpm 500GB HD. Both are at very good prices relative to their retail price. EDIT: also adding to the debate, i realized the 2.66i7 would come with 512MB video card upgrade (from 256MB). So it's: 1) 7200RPM / 256MB Video Card 2) 2.66GHz i7 / 512MB Video Card Thanks!