I will only be running Photoshop cs6 on this desktop (new iMac), so no video, gaming, etc. I already use a Macbook Pro for web work. I also store most of my work on an external HD so storage isn't an issue: but performance is. I really wanted the smaller screen 21.5", but a little worried about the 5400 rpm HD. I will be purchasing 16gb RAM whichever I choose, and shall stick with i5, but I don't want to purchase the Fusion unless it is absolutely necessary. So, I'm now torn between getting the 21.5" with a Fusion drive or the 27" with the default 7200. Please bear in mind I am only using this machine for Photoshop. One Apple rep even said the entry level with 5400 would be fine....so, any opinions? EDIT: I work with layers, digital painting, etc, but not RAW files.