My favorite Firefox plugins

These are my six most favorite plugins for the Firefox web browser, in order of preference.

1. Sessionsaver A friend of mine is a big fan of the Opera web browser. One of the features he appreciates most is that when you start it, you immediatly return to the pages you were visiting the last time you closed it. After he told me this I went looking for a firefox plugin, and lo and behold, there you have it. This one is so nice I hardly think about it any more. It is fully configurable, and even allows you to make a 'snapshot' of the pages you're visiting (say you're researching something), and return there hours, days or weeks later. Requires advanced tabbed browsing to fully appreciate it, see next item.
2. Tabbrowser Preferences This is another one I hardly think about any more, but I wouldn't be able to live without it. I've been a heavy fan of browser tabs ever since they appeared, and this plugin lets you make the most of it. Some of my favorite features : automatically open searches from the quick search bar in new tabs, per tab locking, open requests for a new window in a new tab instead. Again fully configurable as it should be.
3. CustomizeGoogle Remove ads from google search results, add links to other search engines, add links to the Wayback Machine, use Google Suggest to automatically suggest words while you're typing and a bunch of other nifty features to improve your searching experience. These three should, in my totally humble opinion, be installed with firefox by default. These are the type of innovation that you never knew you needed, but once you're used to it you just wouldn't want to be without it.
4. Forecastfox Always have the latest weather report for your area in the statusbar of your browser window. Configurable from the current weather only up to 10 days of forecast. It's really unobtrusive, but also really handy and something that will even impress non-techies. If you're on the road a lot, you can make different profiles for each location you regularly visit.
5. Adblock Simple yet great. Each time you visit a page with unwanted ads (is that a pleonasm), just click the banner and say 'Adblock image'. After a while the system will recognize all the ads from the pages you visit, delivering a beautiful ad-free browsing experience.
6. Web Developer Extension If you're a web developer, this one is a must have. I love it in every way. It's only on the sixth place because it's less general purpose than the other ones. But I love it, I truly do. It adds a toolbar and a context window to do all kind of analysis of the pages you're visiting, resize the browser window to common screen sizes like 800x600, edit the CSS of a page and see the effects in real-time, validate HTML/CSS/RSS, and lots more.

I'd also like to give a honorable mention to GMail manager, and to some great firefox features that don't require a plugin, Tabbed browsing, Quick search bar and Live bookmarks. Please give them a warm applause, they deserve it in each and every way!
For anyone still using Internet Explorer to surf the net, Get Firefox! You will not, I repeat, you will not regret it, ever.

I would like to start a favorite plugin meme, and I'm infecting Floris. The rules : list your favorite plugins for a cross-platform open source program.