I'm about to purchase a 27" iMac playing with a budget around £1500 (≈$2000 in Apples economy). So, I'm torn between the base 27" model and bumping the processor to i5 (3.6 dual) and getting a refurb 27" i7 (2.8 Quad). So questions for you knowledgable people: Is the bump from i3 to i5 worthwhile in the base model? Which will give best overall performance between the refurb i7 and new i3/5? I notice the refurb has the ATI Radeon HD 4850 whereas the new ones have ATI Radeon HD 5670 with the same ram. I've heard the amount of L3 cache can make a difference too and the refurb has twice that of the new ones. I'm slightly concerned about that the refurbs screen might be an issue, are there any other subtle or behind the scenes upgrades from the new models I should think about too? (I use Final Cut Studio quite a bit, but most work done in Adobe Creative Suite, so the machine will be 'put to work' in that sense) Thanks for your thoughts.