[seren6ipity]

This is a default setting. I believe you should be able to modify it on System Preferences>Keyboard and Mouse>Keyboard : Use F1, F2 as standard keys.

[thwarted]

Yes, I know. I was responding to "By default, F11 is an Expose keyboard shortcut on OS X", which is not the case with every released Mac or keyboard.

[Zev]

Sorry about that, I checked the box in the settings that reversed function in relation to F11 being pressed. My primary point, that it doesn't make Firefox go full screen, still stands.