You should definitely make this configurable. I used to use hit a hint (https://addons.mozilla.org/en-US/firefox/addon/1341), but found it would sometimes capture _all_ presses of the spacebar/ctrl key/whatever you configured. This made it practically impossible to enter text on some websites. It started happening more and more often, which meant I ended up turning HaH off.

GleeBox looks great. Echoing another posters comments, the mouse-centric navigation of the web really gets to me. Anything that lessons mouse usage gets my vote!