The plug-ins/extensions that I have found useful include:
- Adblock — to filter adverts from web pages.
- AniDisable — to stop distracting GIF file animation.
- British English Dictionary — to enable spell checking in forms (text boxes).
- Broadband Speed Test and Diagnostics — to test the speed of broadband connections.
- CloseButton — to adds a Close Tab button to the toolbar.
- CoLT —to copy link text.
- Context Search —for search engines on the context menu.
- DownThemAll! — a downloader with built-in download manager; to allow easy download of multiple files with file-type filtering and optional renaming.
- Duplicate Tab — to duplicate a tab.
- FEBE — to backup Firefox data, such as plug-ins.
- Firebug — e.g. to watch HTTP requests.
- FireFTP — FTP client.
- Firefox Throttle — to reduce download bandwidth for large downloads (at work or on another shared connection).
- Flashblock — to stop distracting Flash animations.
- googlebar — from mozdev.org
- Mark Newest Version — to mark the latest version in a file list (e.g. Subversion releases).
- NoScript —for extra protection.
- Open In Window — to open links in the selected window.
- Quick Restart — to adds a “Restart Firefox” item to the “File” menu.
- Searchbar Autosizer — to automatically resize the search bar.
- TortoiseSVN Menu — add TortoiseSVN commands to link context menu.
- Uppity — to navigate up one level (directory).
- Web Developer — e.g. for analysing the composition of web pages.
The following is a useful theme:
- Classic Compact — to minimise the vertical space consumed by menus & tool bars.