My affinity for Firefox comes as much from the fantastic community of addon developers as it does from the program itself. Now, I'm sure you will have heard of some of these before: good Firefox addons tend to spread like wildfire. I hope I've managed to include some that you might have missed.
I've ranked just over a dozen addons that I find to be particularly useful - even to more casual Firefox users.
1. Cybersearch - Customizable Google searches in my Awesome Bar? Yes, please! It also supports keywords so you can enter things like "ds firefox addons" and limit your search to a specific web site .Enter a comma separated list of URLs to search a group of sites.
2. LastPass - I used to use KeePass, but I just like LastPass better. It did a great job of importing (and then removing) my Firefox stored passwords, and its secure password creation tool makes using different passwords on new sites a snap. The web interface is a great way to manage my logins and groups.
3. FEBE - As with anything else on your computer, it's never a bad idea to back up your Firefox install. FEBE will back up everything - extensions, themes, bookmarks - or just what you choose, and you can set up an automated schedule. It's also got integrated Box.net support, which is actually a fairly nice way to roll-you-rown manual Firefox syncing.
4. AdBlock Plus. I don't really use AdBlock because I hate advertisements, but because I don't like waiting for web pages to load. Flash ads and multiple banners really gum up the works, so I depend on AdBlock to keep things running smoothly. It's also a decent way to cut back on your bandwidth usage.
5. DownThemAll - When a friend first showed me DTA a few years ago, I couldn't believe I was still just using FF2's built-in manager. DTA rocks, and would definitely make my Top 5. It's simply one of the best download managers out there.
6. OpenItOnline - I don't do enough work with Office-type documents anymore to warrant installing a suite on my laptop. OpenItOnline lets me send DOC, XLS, and all the other supported file types to ZohoViewer for perusal instead of downloading them. It supports all Zoho and Google Docs apps to open files.
7. Deng Google Bookmarks - I'm not sold on Weave yet, so for now I let Google store my bookmarks. I switched to the Deng addon after using GMarks for the longest time - because I got tired of the giant "bookmark" button on my toolbar. Deng displays only a small star icon, and its management interface is superior.
8. Screengrab! - To quickly capture an entire web page, Screengrab is a great tool. It can save or copy an entire page, the visible portion, or a rectangular selection. If I don't actually need to print a page, Screengrab is an easy, environmentally friendly way for me to keep a copy of it.
9. HP Smart Web Printing - When I do need to print, HP's addon gives me the option to combine multiple web pages on one sheet of paper, eliminate elements I don't need to print, and it even allows saving to PDF. Always nice to see the big boys release something great for free.
10. Web Of Trust - WOT is a great way to keep yourself out of malware trouble. I think I'm a pretty responsible surfer, but I don't know the reputation of every site on the Internet. WOT gives you a heads up about the trustworthiness of a link (based on community input) before you visit it.
11. Shareaholic - Anyone that enjoys sharing links would do well to install this one: it supports a ton of services, including Digg, Delicious, Twitter, Pownce, Reddit, Facebook, MySpace, and Google. It's also a quick way to see how many Diggs or Delicious bookmarks a page has received. Bzzster support gives quick access to sharing items via email.
12. Pingfire - Another must for the social surfer. Ping.fm's multiple-site update service is rad, and Pingfire kicks it up a notch. No need to even visit Ping, just add the Pingfire icon to your toolbar and update your microblog and status sites with ultimate ease.
13. Tab Kit - It's got a whole slew of options for tab management: grouping, coloring, sorting, protection, mouse rocker and scroll wheel support, and many, many others. Visit the devloper's page for a full list of features.
14. Yet Another Smooth Scrolling - Firefox's default scrolling isn't quite as refined as I like it, so I use YASS to tweak things until they're just right. It supports up to three presets, which is nice for laptops. Keep one set for your touchpad and one for your mouse.
Sid I miss your favorite? Share it in the comments so our other readers don't miss out!