Here i am mentioning some of the firefox add-ons which makes me say ‘Wow’ in a not geekish way. Though this is late but i found them just today and could not restrain myself from sharing these to all 
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Cooliris
Full-Screen, 3D — Cooliris transforms your browser into a lightning fast, cinematic way to browse online photos and videos.
This takes image/video searching in a new height. Must see.
It’s better than FastDial in sense of look … But i like them both. 
Let me know if you have seen such kind of innovative add-ons or application .. Do share. 
tohin said
My most Used addons list:
Firebug
Y-slow
Fireshot
Greasemonkey
Web Developer Toolbar
Auto-pager
Ad-block plus
StatusbarEX
ColorZilla
Readit later
.. there are more..