I've got to say that I am really digging the tabbed browsing experience that Firefox gives you. I've also been waiting to see what kind of alternate engines you could add from :mozdev.org.

They finally seem to have the site up (at least it was unavailable when I went there initially). They have what I was most hoping for, a dictionary plugin. Now finding a word is just as easy as searching google. No having to go to the site directly.

Good job mozdev people!