I'm planning on replacing my old iMac with a new one. I'm leaning towards the 27" iMac, both for the screen space and the Quad-Core i5 Processor. My most taxing uses of the computer will be Photoshop and video editing with Final Cut Express (which I'm dying to try out!) Considering my intended usage, and also that hardware upgrades are impossible (?) after purchase, I'm wondering if I'd see a worthwhile benefit from the i7 processor and/or a dual-drive set up with an SSD? Also, I maxed out my current iMac on RAM from Crucial when I bought it; is aftermarket RAM still the way to go? Thanks in advance for any tips!