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Windows XP Media Center Edition
This edition is designed for media center PCs. Originally, it was only available bundled with one of these computers, and could not be purchased separately. In 2003 the Media Center Edition was updated as "Windows XP Media Center Edition 2003", which added additional features such as FM radio tuning. Another update was released in 2004, and again in 2005, which was the first edition available for System Builders.

Internet Explorer 6 running in Windows XP Tablet PC Edition.
Windows XP Tablet PC Edition
Intended for specially designed notebook/laptop computers called tablet PCs, the Tablet PC Edition is compatible with a pen-sensitive screen, supporting handwritten notes and portrait-oriented screens. It cannot be purchased separately from a Tablet PC without an MSDN (Microsoft Developers Network) subscription.
Windows XP Embedded
An edition for specific consumer electronics, set-top boxes, kiosks/ATMs, medical devices, arcade video games, point-of-sale terminals, and Voice over Internet Protocol (VoIP) components.
Windows Fundamentals for Legacy PCs
In July 2006, Microsoft introduced a "thin-client" version of Windows XP called Windows Fundamentals for Legacy PCs, which targets older machines (as early as the original Pentium). It will only be available to Software Assurance customers, who would like to upgrade to Windows XP to take advantage of its security and management capabilities, but can't afford to purchase new hardware. Applications will typically be run on a remote server using Remote Desktop.