I'm not as in to the Mozilla stuff as I was a year or so ago, but I decided to test the auto-update facility that they have lined up for Firefox 1.0. I fiddled with some settings in my 1.0PR and hit the big red button.
Boom.
Well, not quite. The update downloaded, but it destroyed my profile. I've deleted it now, and still things aren't working - the back button for one. I really hope, for Mozilla's sake that I am a big freak of nature and the Firefox 1.0 release doesn't do this to too many people...