This tip applies to both GIMP 2.6 (last major version) GIMP 2.8 (the current version) and all future planned versions of GIMP.

You may notice that the toolboxes in GIMP can take up a fairly large part of your screen, and sometimes you want to use that area for your canvas instead. Well good news! By simply hitting the Tab key on your keyboard those toolbox windows or docks will disappear.  The same key will bring them back when you need them again.

I realise that most of you probably know this already, but I have met a number of people that don't know or use this feature of GIMP, and get frustrated with the interface being too large, so I thought I should share it.