I did a full reinstall this weekend using a slipstreamed XP Pro with SP3. There were zero problems and it is running smoothly. I used Nlite to do the slipstream and I added all my device drivers to the cd so that the install found them. I used the SP3 that MajorGeeks had last week for download.
After the install, I tweaked it just the way I like it, then I made a disk image using Acronis Trueimage 9. I always keep an image of a base install without any added software. That way I am only 5 minutes from a fresh install at any time. For that reason, I do not run a software firewall or antivirus. But, I've never had a virus anyway.