I got Navigator 9's official EOL notice last week. But FF3 still isn't quite ready for me. Navigator 9 Migrator tool / extension is absolutely useless.

UPDATE: I'm now on FF3 full time and loving it. I'm still missing a couple of features though:

I still need some extensions to migrate fully:
* Undo Closed Tabs
* Firebug

and really really want (almost need):
* Mac Favicon XL (theme)
* Google PageRank Status, or SearchStatus (enables Google web history)
* It's All Text!

And would like
* Html Validator
* ColorZilla
* dragdropupload
* Email This!
* ShowIP
* Gmail manager (Gmail Notifier is okay for the interim)
* ErrorZilla