I decided that fewer things would need extending on the Mac so it's easier to have that one round the corner eg my speakers wouldn't reach the PC whereas I don't have external speakers on the Mac, and my keyboard would also need extending whereas the Mac's keyboard plugs into the monitor's ADB ports rather than into the tower. On the Mac the display cable is the only thing that isn't long enough (the USB mouse isn't long enough and has to be extended even with it under the desk). Also I'm getting one of those PC cases with a transparent side and lots of lights and things, and the space round the corner is in between two other things where the side window would be mostly hidden!