Windows XP SP3 will be released to existing Windows XP users tomorrow, Tuesday, April 29. It's been in the works for a very long time, but despite its protracted development time, some users, such as cNet's Michael Horowitz, are advising users to wait before installing SP3.
A fundamental tenant of Defensive Computing is not to install newly released software. With Windows XP SP3, the reason to wait is software incompatibilities. Even though SP3 has underdone much testing, it's a big world and there are bound to be problems with some software. By waiting, you let everyone else find and fix the problems before you face them.
Sounds like good advice, but does Horowitz have any specific reasons to be cautious about SP3? Actually, yes. He points out that Mac users running Windows XP (you know who you are) must upgrade to new versions of Apple's BootCamp boot loader and VMWare's Fusion virtualization software to use SP3, and notes that the April 23rd edition of The Personal Computer Show included a discussion by host Joe King of how SP3 'broke' his Trend Micro product until a 90MB+ "patch" was installed and a revised serial number was provided.
Horowitz recommends creating an image of your XP SP2 installation before installing SP3. You can use Norton Ghost 12.0 or higher (new version is 14.0), Acronis TrueImage 11, or others. He also recommends creating a restore point with System Restore.
Unfortunately, application vendors might not yet know that some of their products don't work properly with XP SP3 until after it's released to the mass computing public. While you're downloading SP3, check with vendors to see if they have any updates or application notes posted before you install SP3.