Firefox add-ons I could not do without

I've been using Mozilla Firefox for quite some years now. There are a lot of things I love about it: the history browser, the bookmark organizer, tabbed browsing, support for Linux, Mac OS and Windows, open source ... But the thing that makes Firefox stand out, is it's add-ons.
Opera is another strong browser, but it comes with this load of features I don't need. Unlike Firefox, you can't choose which extras you want. Opera obliges you to use this and that. But I don't want that. I would rather have the choice of my own extra features and Firefox has the best and most choice to do just that.
But often with Firefox add-ons, you can't see the wood for the trees. That why I'm going to give a list of add-ons I can't live without.



