When a keyboard is connected to a projector to run PowerPoint slides, my favorite is Letter ‘B’. Hitting it causes the screen image to go black. The projector is still on and hitting ‘B’ again shows the last slide up. With a properly designed audience-centric presentation that has specific periods without any slides, ‘B’ makes it easy to avoid having slides up too long or too early.
Simple and easy … see why it’s my favorite letter?