Hello, I'm a graphic designer and the most I ever require from my mac is working with 300dpi files or 100-150gb tops files in photoshop, perhaps RARELY running 2 or 3 large files at the same time. I don't install much software other than the Adobe Creative Suite and I don't put any music on itunes, I carry it in my iPod instead. I'd like to have it not get any slower for as long as possible. My question is, do I buy: 1. Low end 21.5" iMac 2. Low en 21.5" iMac + Fusion Drive 3. High end 21.5" iMac 4. High en 21.5" iMac + Fusion Drive Thanks!