We have tested AutoCAD 2005 with Microsoft Windows XP Service Pack 2, and found no issues but I cannot speak for the AutoCAD based or vertical products. There is one minor issue discovered with the Autodesk DWF Viewer and the solution is documented and will be posted to the online knowledge base at http://support.autodesk.com. You can find details of the minor issue and the solution in the Autodesk DWF Viewer discussion group. Click Here
I have been running the Windows XP Service Pack 2 for over 6 months and it made my system faster, more secure, and more stable. I have used it with most Autodesk products with no issues noticed except the info bar alerts when viewing DWF but that is minor and Microsoft and Autodesk are researching it.
Some have reported AutoCAD as having problems with Microsoft Windows XP SP2 such as Ralph Grabowski in his WorldCAD Access blog. This is misleading as the problem is just that when using the FTP option in the File Open dialog is blocked under Windows XP SP2. This is expected as there is a firewall built-in and activated in the new Windows XP SP2 and this would be the same from other activated firewalls as the FTP access requires port 21. Microsoft may hopefully be clearing up this statement and confusion in their knowledge base article as there is no specific issues with AutoCAD and Microsoft Windows XP SP2. I spoke with Microsoft just this morning, as they work very closely with us and in fact use AutoCAD and other autodesk products in their Operating System and Service Pack testing labs.
Microsoft Windows XP SP2 is a step in the right direction for security on the number one operating system Windows XP and should not be ignored nor put off as it adds many new abilities and some serious security enhancements.
For more on the Microsoft Windows XP Service Pack 2: