Incra makes a standard protractor more useful. Rather than trying to mark next to a tiny line on the edge of a protractor, every 5º and every 22.5º they machine long slots for marking lines with a really sharp pencil or a 0.5 mm lead mechanical pencil. For less frequently-used angles they also cut short slots every 1/2º.
Instead of trying to line up the protractor along an edge, you can quickly butt the protractor’s T-bar against the edge of your work piece. When you need to use the protractor in the middle of a piece, the T-bar detaches with two thumb screws. With the T-bar removed, you also have access to a 6″ ruler with marking holes every 1/32″.
Pricing for the protractor starts around $26 including shipping. You could probably by a digital protractor for just a little more, but with the Incra at least you’ll never have to scramble to find batteries. For the Imperial unit-challenged, they also sell a metric version where they replace the 6″ scale with a 160 mm scale.