[Osiris]

Did you ever feel that some of the right-click and menu options are completely useless ? I know of several that I’m never using, want some examples ? Work Offline in the File menu, Send Link in the right-click menu or For Internet Explorer Users in the Help menu. Removing entries increases the usability because it makes it easier to locate the right options putting them more into focus.
Menu Editor is a Firefox extension that lets you remove unwanted menu entries from Firefox. Available are the right-click main window and tab context menu plus all Firefox menus like File, Edit and View. Every entry can be removed so be extra careful when removing some, you might need them in a later stage. Another option is to remove a menu completely.
The right-click menu has been changed the most on my system. I never use the image to background image feature, back, forward or stop and I never save or send links. Take a look at the before and after size of the menu:

On a side note, this extension is also working in Thunderbird. If you want to use it in Firefox 3 beta you need to make it compatible before you can use it. Either use the Nightly Tester Tools or change the version manually.
Found at the Inspired Geek

Firefox Menu Editor