The first thing I miss with a fresh install of Firefox is my own Copy as HTML Link extension, which I end up using almost daily in the course of blogging.

Out of habit, I install Firebug, the Web Developer Toolbar and Live HTTP Headers. I don’t use them that often (outside of work), but they do come in handy when troubleshooting web pages.

LastTab is one of those extensions I can’t live without. It modifies the behavior of Ctrl+Tab to switch between most recently viewed tabs (like Alt+Tab does with windows in the OS), rather than just moving forward one tab. (This should be core Firefox functionality, imho!)

I scanned through about 1000 of the most downloaded extensions at Firefox Add-ons and of those really only one caught my eye. Source Viewer Tab opens view-source windows (Ctrl+U) in new tabs, instead of new windows. Together with LastTab, I can see this becoming indispensable.