Hello, I'm purchasing a new iMac with the intention of using primarily for photo editing. I've been trying to decide between the i5 3.6 and the i5 quad core, as well as the 1gb graphics card and the 512mb graphics card. Most people tell me to just get the higher powered hardware regardless, but, for using lightroom for editing photos, is all that power really needed compared to the 3.6 i5 and the 512mb card? I don't want to overpay for hardware not needed since I do see myself looking to upgrade the glass for my DSLR in the next year or two as well. If there's anyone out there with Lightroom on similarly configured iMacs that can share their input I would be extremely grateful. thanks!