I love Firefox. Usually it goes hand-in-hand with Defensive Computing, as Firefox is more secure than Internet Explorer. But not today, not with the release of version 3 of Firefox.
Don't install Firefox version 3. Not today. not for a while.
Like all new software, Firefox 3 is best kept at arms length. Version 3 was a long time coming and, no doubt, features lots of new code. At the risk of repeating myself, all new software contains bugs and design flaws. Let the rest of the world debug it for you.
This is not to pick on Firefox or Mozilla. Recently in this blog, I suggested waiting on Windows XP SP3, which turned out, in retrospect, to be the right thing to do. I also suggested holding off on Vista and Leopard when they were new. How long to wait is a matter of opinion. However, waiting rather than rushing, is always the right defensive approach.
And, when the time comes to try Firefox version 3, go with the portable version available at portableapps.com. It can happily co-exist with a normally installed copy of Firefox. The only limitation I've found is that if the normally installed copy of Firefox is running, the portable version won't run (see below).
Finally, another repeat suggestion. Windows XP users should run all their web browsers under the free DropMyRights program. I wrote three postings about this last August. See Every Windows XP user should drop their rights.
Update June 17, 2008: Let me clear up some confusion about portable applications in general - they are not "installed", at least as far as Windows is concerned. When you run an EXE file downloaded from portableapps.com it looks like a normal installation and they even use the word "install" (an unfortunate choice). But, all that is really happening is the application is unpacked/unzipped into whatever folder you point it at. To delete the application, delete the folder. There is no un-install.
Update June 18, 2008: Today, Robert Vamosi wrote Firefox 3 suffers its first vulnerability. This is not what I was referring to here, as the problem, whatever it is, also affects version 2 of Firefox.
Update June 19, 2008: Firefox version 3 is now available as a portable application at portableapps.com. Even if you are not concerned about major new software releases, running the portable version 3 on the same computer as a normally installed copy of version 2 is a great way to compare the two.
Update July 2, 2008: Firefox version 2 is a great web browser. Today, they released an update, version 220.127.116.11. I mention this here because version 14 of Firefox 2 contained 13 bugs, five of which Mozilla rated "critical." That the 14th go-round still contained 13 bugs confirms my reluctance to convert immediately to the first release of a major new version.