CheatSheet for OSX - all the keyboard shortcuts, all the apps, all the time

I came across this fantastic little app the other day called Cheat Sheet. For any programme, at any time, if you hold the Cmd key for a few seconds on its own, up pops a window with a list of all of the available keyboard short cuts & a description. I don't know about you but I only ever remember a few, Cmd+Shift+D to send an open email is one of the very few I've ever committed to memory.

CheatSheet is free, customisable and does exactly what it says on the tin, no Mac user should be without it.