After updating to Firefox 3.6, I started having issues with WebDeveloper, the single favorite Firefox extension I’m using on an almost daily basis.
Namely, the keyboard shortcut I was using most frequently ⌘-⇧-F had been overwritten by the latest Firefox update; instead of calling the ‘Display Element Information’ function from WebDeveloper, it now called View in Full Screen mode.
Frustrating, to say the least.

Since I didn’t want to change my typing, a bit of Googling led me to KeyConfig, an amazing Firefox extension (more info here http://forums.mozillazine.org/viewtopic.php?f=48&t=72994) which allows you to change almost ALL keyboard shortcuts in Firefox and the installed extensions.

Hope this proves useful to someone else as well.