I've nearly always used my MacBook in clamshell mode when at the office, with everything running off a big screen and an external keyboard, trackpad etc. But obviously with the newer MacBooks and Pros, that's a waste of a very nice retina screen. So for those of you who use a laptop not-in-clamshell mode, how are your desks setup in terms of position? Laptop dead centre as the main screen, external monitor off to one side? Laptop on a riser, external keyboard and trackpad? Laptop off-centre as a secondary screen? Thanks!