The latest version of the excellent Opera web browser is out. I've been using it for about an hour on an XP Home machine and it seems fine. There are a few puzzling changes from the beta, but they seem to be all for the better and I'm a happy camper.
The link is to an Opera blog, which is a good place to find out what Opera offers and what you can expect. Remember; there are no ads in the free download any more. It's a safe and very serviceable alternative and just different enough that you may find it suits you better than Firefox.