One of the first screens you are presented with when installing Windows XP Service pack 3 (from the CD version) is one that asks “What to know before installing Service Pack 3.” A useful feature you would think, except that when you click the link a page opens in the browser headed “More information about installing Service Pack 2” and says “2” all the way down so I have no idea if any of it is relevant. If you click through to the “Readme” it seems to be more about SP3.
This may be a trivial point but doesn’t encourage confidence in the Quality Assurance at Microsoft.
Update: 29 May 2008—Although I have had no trouble with SP3, having now installed it on 4 desktops, 2 laptops and one virtual machine, there are strong reports about some problems. In particular owners of HP machines using AMD processors should hold off as should users of Norton Internet Security (well knock me down with a feather).