The Home and Professional editions of Windows XP are nearly identical, the only differences are additional features found in the Professional edition that most likely won't appeal to home users. The primary differences, aside from the price and the color of the packaging, are as follows:
Windows XP Home Edition
-Contains basic support for security among multiple users.
-Built-in support for peer-to-peer networking, but only for up to five computers.
-The backup utlity is not installed by default, but is included on the CD.
Windows XP Professional Edition
-Includes extended support for security between multiple users on the same machine.
-Better support for peer-to-peer networking, plus support for joining a "Windows NT domain."
-The backup utlity is installed by default.
-The Professional edition includes the following components not found in the Home edition:
-Administrative Tools (in the Start Menu and Control Panel)
-Automated System Recovery (ASR)
-Boot Configuration Manager
-DriverQuery
-Group Policy Refresh Utility
-Multi-lingual User Interface (MUI) add-on
-NTFS Encryption Utilitiy
-Offline Files and Folders
-OpenFiles
-Performance Log Manager
-Remote Desktop
-Scheduled Tasks Console
-Security Template Utility
-Taskkill
-Tasklist
-Telnet Administrator
-Provides support for multi-processor systems (2 or 4 CPUs), Dynamic Disks, Fax