One tool system administrators take advantage of when fine tuning how how servers work is by utilizing the Local and Group Policy Editors. These tools allow you to control virtually every aspect of security and behavior of your Windows machine.
One great thing about Windows XP Pro is it includes the policy editor, but it can be intimidating for normal users to use. Additionally, XP Home doesn’t have this, leaving users to have to modify the registry. The better alternative to both of these is the free Windows XP Security Console program by Doug Knox.
The program puts all the modifiable features into convenient check boxes so you can get all the control without any of the confusion. I definitely see this tool being useful for both normal and power users.