If I could put together an extension suite, I would create a Tweaking/Troubleshooting Suite which would include four very useful extensions; about:config, ChromEdit Plus, Infolister and Nightly Tester Tools. I will go into a brief summary of each of these extensions below. For more detailed information, click on the extension name.
about:config – adds toolbar icon to open ‘about:config’ in a medium size pop-up window. Very handy as you don’t have to keep switching between tabs (twek directions are in one tab and ‘about:config’ is in another).
ChromEdit Plus – automatically locates and allows you to edit your (based on the profile currently in use) userChrome.css, userContent.css & user.js files. Also provides short cuts to Open Profile Folder, Open Chrome Folder, Open Install Folder options and adds a restart Firefox button.
InfoLister – Generates in a new window, a complete listing of all your Extensions, Themes, Add-Ons plus detailed information about the current version and build of Firefox running. Very useful for troubleshooting when asked, “So what extensions and themes you have installed?”
Nightly Tester Tools – Allows you to force icompatible extensions to work in your current version and build of Firefox. Useful for extensions that simply haven’t had their Max Version setting bumped up to the more recently releases of Firefox (or Thunderbird).