Question for the Mac Pro users with elderly editions. How many years before you felt like your Mac Pro was starting to show its age? I'm not talking about for your power user uses. Just normal stuff, some gaming, and some light home movie video editing (like vacation videos with no time crunch to do any of the compiling). I've got a buddy who just does casual stuff on his computers but always buys Mac Pros and he tends to get well over 6 years of use out of them before he replaces them. He feels like that is the way to go over iMacs because he gets years of high end power and then years of sufficient power to run the latest OS and it gives him better value than buying an iMac every three years or so. Also he runs less risk of a fatal hardware error since parts are more easily replaceable. I've never made the switch instead always dropping the $1800 or so for a decent iMac. But I wonder if retina level desktop screens will soon be available and if that will be compelling reason to switch to the big box. It might be worth it if I think I can get 6+ years out of the Mac Pro and then 10 years out of the external screen (maybe longer).