In case you Powerbook users out there haven‘t bumped into uControl yet, you should. For me it does at least two invaluable things: first, it makes my trackpad act as a vertical and horizontal (!) scroll wheel. Second it gives me my function keys back as I can swap the behaviour: Apple‘s added functions (dimming the screen, controlling the volume and keyboard lighting) now are only accessible with the fn-key and I got 12 extra keys for my personal use without hitting any modifier keys.