I work in academics and am looking for a desktop as I need a bigger screen for writing. I currently have a mid-2009 MBP which I've upgraded to 8GB of RAM and installed an SSD drive, but still have problems with speed. I'd like my new iMAC to last for a while and was wondering if I should go with the 4K vs 5K. I was thinking 4K since the 5K initially seemed too big, but I've read that the 4K is lackluster for the price. My main wish is that this computer will last me a while with minimal upgrades. So my question, which computer should I get for mainly word processing with bibliographic software and multiple windows, and intermittent movie watching and photo editing. Do you think the 4K + fusion drive is sufficient or should I get the 5K with fusion drive since the 5K gives me the option to increase memory on my own at a later date. I am flexible with price. I appreciate your thoughts.