Windows XP featured a new task-based graphical user interface. The Start menu and Taskbar were updated and many visual effects were added, including:

Windows XP analyzed the performance impact of visual effects and uses this to determine whether to enable them, so as to prevent the new functionality from consuming excessive additional processing overhead. Users can further customize these settings.^[17] Some effects, such as alpha compositing (transparency and fading), are handled entirely by many newer video cards. However, if the video card is not capable of hardware alpha blending, performance can be substantially hurt, and Microsoft recommends the feature should be turned off manually.^[18] Windows XP added the ability for Windows to use "Visual Styles" to change the user interface. However, visual styles must be cryptographically signed by Microsoft to run. Luna is the name of the new visual style that ships with Windows XP, and is enabled by default for machines with more than 64 MiB of RAM. Luna refers only to one particular visual style, not to all of the new user interface features of Windows XP as a whole. Some users "patch" the uxtheme.dll file that restricts the ability to use visual styles, created by the general public or the user, on Windows XP.^[19]

In addition to the included Windows XP themes, there is one previously unreleased theme with a dark blue taskbar and window bars similar to Windows Vista titled "Royale Noir" available for download, albeit unofficially.^[20] Microsoft officially released a modified version of this theme as the "Zune" theme, to celebrate the launch of its Zune portable media player in November 2006. The differences are only visual with a new glassy look along with a black taskbar instead of dark blue and an orange start button instead of green.^[21] Additionally, the Media Center "Energy Blue" theme, which was included in the Media Center editions, is also available to download for use on all Windows XP editions.^[22]

The default wallpaper, Bliss, is a BMP photograph of a landscape in the Napa Valley outside Napa, California,^[23] with rolling green hills and a blue sky with stratocumulus and cirrus clouds.

The Windows 2000 "classic" interface can be used instead if preferred. Several third party utilities exist that provide hundreds of different visual styles.