Firefox 2.0 is out. Frankly, not many things of direct consequence have changed and the best of those that have should have been included a long time ago (tab closing undo, session resuming, and tab arrows)… but there’s integrated spell check (!) and that and a painless installation (most all your extensions will follow you along painlessly) make this a must.
Update 28/Oct/2006: FF2’s find-as-you-type now searches inside textareas too! I used to copypaste back and forth between Vim and a textarea just to jump to particular text spot. Ahh… the joy!