Here are some of the Firefox extensions I use(d) regularly:
- Adblock Plus: Blocks annoying ads.
- AddThis: Post pages to various sites and services like Gmail, WordPress, Facebook from the context menu.
- Auto Shutdown NG: Fine tune what to do after download is complete and you are not available.
- ChmFox: View CHM files in Firefox.
- Copy Plain Text: Copy text from a page as plain text without formatting.
- FDV Speed Dial: Saves a lot of typing. Can create dial images from default site images instead of site previews.
- Flashblock: Stops flash videos from streaming automatically.
- InstantFox: Address bar shortcuts and suggestions.
- New Old Menu: Return to the old menus of Firefox.
- QuickDrag: Extremely useful. Drag and open an image or a link in a separate tab.
- Resurrect Pages: Get server-cached pages when a site is down.
- Side Tabs: Place tabs in a sidebar. Great for widescreen laptops.
- United States English Spellchecker: Detects spelling mistakes in typing.