>The ones that still don't are the ones I can live without (like Firebug - I'll need something like that next time I develop a web app, not sooner), with the honorable exception of mouse gestures, which I really wish I had again. There seem to be nice replacements available.
>
>Other than that, everything important does work.

The firebug extension is available for FF3 at https://addons.mozilla.org/en-US/firefox/addon/1843.