I finally upgraded to Firefox 2.0 because I had to for work -- and I love it and wonder why I waited so long! The only feature I'm really digging is the spellcheck, but with my lousy spelling that's enough to totally win me over...
Also, I'm finally trying some add-ons. In fact, this post was written using the Performancing add-on -- not that I'm recommending it yet, this is my first time using it...