A bare copy of Firefox is a wonderful thing, but when you start stuffing it with add-ons it gets even better. So what are the best add-ons for power users? Here's our top 25:
1. All-in-one Sidebar
All-in-one Sidebar makes Firefox's Sidebar more useful by displaying pretty much anything you might want: source code, downloads, add-ons, page info, entire web pages…
Jealous of Safari's Porn Mode – ahem, Private Browsing? Now you can have it too, with Stealther.
3. Web Developer Toolbar
The name's a clue: the Web Developer Toolbar adds a toolbar containing useful tools for web developers.
More Here