Firefox Extensions

Google Browser Sync - http://www.google.com/tools/firefox/

del.icio.us - https://addons.mozilla.org/firefox/1532/

Fasterfox - https://addons.mozilla.org/firefox/1269/

Flashblock - https://addons.mozilla.org/firefox/433/

DownThemAll! - https://addons.mozilla.org/firefox/201/ - http://www.downthemall.net/

Tab Mix Plus - https://addons.mozilla.org/firefox/1122/
Links: Open windows from other applications in: New Window
Events > Tab Opening: Open new tabs next to current one
Display > Tab Bar: Show New Tab Button
Display > Tab: Width: 100 to 250 pixels

StumbleUpon - https://addons.mozilla.org/firefox/138/ - tried for a bit and really haven't gone back to.