Microsoft’s recent release of Windows XP Service Pack 3 has resulted in several problems and incompatibilities, one of which was their own retail software. I bit the bullet and installed SP3 on a helpdesk machine (dumb, I should have known better than to put a new Microsoft service pack onto an important computer.) and all of a sudden I lost the ability to control my firewall settings and ports that were previously open where now locked shut. It required that I reset the registry in that area to get it working again.
The only difference I’ve really noticed so far in general usage once I got the firewall working again, was that it seemed to get to the login screen faster. Other then that, I’ve not noticed improved speed or stability, so I’m thinking it’s probably something of a non event for most people if you can get it installed correctly. (not everyone has as can be seen by several articles like this and this showing up on the net.)

I’ve heard a couple of people at work speculate that Microsoft would probably love for XP to get some of the bad press Vista has enjoyed up till now, in the hope it might convince people to “upgrade” to Vista. I have no idea of any truth to that, but I must admit that I thought SP3 would make XP slower so Vista didn’t seem so bad by comparison, and that has not turned out to be true, at least not in my experience so far.