If you have an Apple keyboard (or a third party one with similarly branded function keys) you can bring up various system preference panels without using your mouse at all.
Simply hold down the Option key combined with one of the Apple-branded function keys to bring up the related preference panel. So Option+F1 or Option+F2 will bring up Displays.
On the newer keyboards Apple changed the layout of a few of these function keys so they could include iTunes control keys; Option+ those f-keys used to bring up iTunes (under 10.5 and maybe the early versions of 10.6?) but that does nothing now.
Option+ any of the volume keys will bring up the Sound System Pref, and Option+ any of the Exposé function keys will bring up the Exposé/Spaces System Pref.
On a related note -- those newer Apple keyboards no long designate F7 as a toggle for display mirroring/extended desktop modes -- but you can still do that toggle without going into the Displays Pref panel; just hit Command+F1.
[crarko adds: I haven't tested this one. I mostly prefer the older style keyboards, and in fact I'd use the old ADB Extended Keyboard if I could.]

