since the extensions are not too hard to find on the site, I will let the willing find the url's ...
Tab Mix Plus ... it has a lot of options to mess with the tabs and make them perform and look more to your preference.
Tab Catalog ... have a lot of tabs and windows open? roll over this icon at the top (or where ever you put it if you change the way the window looks
as I do) ... it will jump to a page that shows thumbnails of all your open tabs seperated by each window it is open in. Works great for researching
while typing and you want to jump back and forth, but not sure which tab it was, but would know it if you saw it
Visual bookmarks ... has a thumbnail of the page you put into its own folder separate of you normal bookmarks.
zotero ... does some cool stuff, I haven't played with it enough yet.
Save Complete ... saves a webpage correctly.
RealPlayer Browser Recorder Plug-in ... I got it with the RealPlayer Beta and it comes with the new full (free) version. Download virtually any
video you come across. the icon to download pops up above the top left of the video.
Preferential ... advanced preferences
PDF download ... save it, view it, view it with an external viewer, or view it as HTML
OpenBook ... customize how your add bookmark option operates
foxytunes ... control most music players from the bottom of your browser
forecastfox (or forecastfox enhanced) ... local weather at the bottom of your browser.
Exif Viewer ... view the exif data of files
download statusbar ... view and control downloads from a toolbar that appears at the bottom of the window instead of the separate small window (you
still have to go to tools to clean out the download history i think)
Broadband speed test and diagnostics ... for use if a page/server/browser/connection is messing up
bookmark duplicate detector .... finds duplicate bookmarks, warns you before you make a duplicate bookmark
in addition to the ones said previously and some I forgot about
as far as themes, I usually use aquatint black or currently pearl fiber ... until I learn to make my own.