Firefox 1.0 is out. The web server is slashdotted, but you can download it via the firefox ftp server. It would probably be sensible to wait a few days until all the themes and plugins get updated. I'm finding that the servers for those are either non-responsive or underpopulated—and stuff from earlier versions doesn't work.
Note also that you have to uninstall any previous versions of firefox before installing this one, but that in my case at least doing the uninstall didn't delete my profile or bookmarks. And I followed instructions and installed the new version in a different directory from the old one.
For what it’s worth — I didn’t bother doing the uninstall, and I had no problem whatsoever installing the new one.