Top 10 list of Top 10 Firefox add-on/extension lists

Hope this is of some help? I made good use of it though..

Download.com: Best extensions for Firefox 2
Webware.com's brothers at Download.com have a good general list, as covered in this post.

About.com: Top 10 Firefox Extensions
A collection of some of the most popular and useful general Firefox extensions.

Irfan Habib: My Top 10 Firefox Extensions
A thoughtful list for serious Firefox users. See also the comments to this post, which point to other good extensions.

Read/Write Web: Top 10 Firefox Web 2.0 Add-ons
The focus is on effective browsing, bookmarks, and RSS. A good line-up if you explore the Web a lot and want to keep track of things you find.

The Simple Dollar: 10 Firefox Plugs That Save You Money
Love the premise, even if it's stretched a bit thin in this list. This ia a unconventional list of extensions that, one way or another, can impact your pocketbook.

CyberNet: 10 Great Firefox Extensions for Tabbed Browsing
You can push Firefox's breakout feature, tabbed browsing, to the limits if you use the extensions in this list. CyberNet also has a Top 10 list of privacy and security extensions.

Quick Online Tips: Top 10 Extensions to Manage Firefox Extensions
If you need this list, your Firefox setup has gotten way out of hand.

The Moleskin: Firefox Extensions For Web Development
If you're writing your own extensions, see this list.

Mozilla: 10 Most popular Firefox Add-ons
Maybe it's cheating to include this list, but if you want to know how everybody else is tweaking out their browser, don't neglect to go to the source.

Lifehacker: Top Firefox 2 config tweaks
Neither a list of extensions nor numbering 10, this is a tutorial, with excellent examples, on tweaking Firefox's many internal settings. A lot of the things you can do with these tweaks preclude the need for extensions, so it's worth checking out.