Here are firefox add-ons I use regulary:
FlashBlock – This isn’t redundant, it gives more control over when Flash runs.
It’s All Text – IAT lets the user choose a text editor for entering text in website forms. This can be helpful if a user needs to add mark up tags (such as if you were to configure Nvu or another HTML editor, or a text editor that supports mark up languages) or wants to use something a little more powerful than a form text box. You can set it up with just about anything. Or you can just type in the standard form text box if that suits your fancy.
Block Site – My new favorite. This one uses black and white lists to manage incoming content from any server. The cool part is blocking everything ad-related. This should be merged into firefox — it would make the image blocking utility even more powerful.
Download Statusbar – This is better than firefox’ default popup download manager. It can be configured to personal tastes, including changing colors based on download speed. It allows you to keep doing what you’re doing without finding the download manager — just look at the status bar and see the progress of your download(s). I think this should be integrated into firefox and get rid of the old popup download manager.
Sage – I think this is the best RSS reader for firefox. It runs in the sidebar (or can be set to open in a page). It has several options to make it fit the user’s needs, and it can import and export OPML. It’s also themable. This should also be integrated into firefox; the RSS tools in thunderbird should be ditched altogether.
Gmail notifier – Notifies user of new gmail. Can be set to check as frequently as user desires. Can handle multiple gmail accounts. Gives a pop up notifier like any other e-mail tool. It also uses https for gmail by default — so it’s safer than just surfing in to http://www.gmail.com. The user can disable secure server. But why?
Ymail notifier – Like gmail notifier but for yahoo mail accounts. Too bad yahoo mail doesn’t use https.
Deepest Sender – This is a blogging tool that works with a few different blogging formats. It’s not equally developed across platforms. The WordPress part of it is functional but not as complete as other formats; of course, I use WordPress. Missing functionality aside, I really like it and the ability I have to launch it over a site, edit stuff, and send from one interface. I’m using it now and it’s much preferable to using the WP Dashboard. I wish it would allow multiple categories and work for pages. Maybe in a future version.