XP Home vs. XP Pro
Paul Thurrott's SuperSite for Windows: Windows XP Home Edition vs. Professional Edition, What's the difference?. This is the first PC I've bought that uses XP Home instead of my buying XP Professional from the Microsoft Company Store. I have to say having used it for a while at work, I'm not sure it is that important in a small business environment.
We don't use Active Directory and we don't need lots of permissions for desktop users. Saves quite a bit the list is $99 for XP Home and $149 for XP Professional when you are building up a laptop.