As a security person I hear what the best build way to build computers system that I can baseline them . I use tools like MDT 2010.
The Microsoft Deployment Toolkit (MDT) 2010 is a FREE tool that will allow you to create images for operating systems. This tool will script the building of operating systems XP service pack 3, Vista, Windows 7, Server 2003, Server 2008, Server 2008r2. You can also add applications, and configurations.
If you have SCCM or use WDS you can take the results created by this tool. It also has method for upgrading XP to Windows 7 while leaving user data on the system. There is a tool called USMT (User state migration toolkit) using you can specify what data you like to keep on the computer or move to a share during a upgrade.
You can download the beta 1 at https://connect.microsoft.com/site14/Downloads/DownloadDetails.aspx?DownloadID=8689