Windows XP has been the most popular of Windows OS in the recent past, With Windows 7 around the corner launching on October 22nd 2009, and you don’t want to miss the default Windows XP UI., ie., theme in Windows 7 as well then you can try out the Windows XP Luna Theme ported for Windows 7 by Satukoro from DeviantArt.
Here’s a screenshot of the ported Luna theme on Windows 7.
Downloaded Luna Theme for Windows 7. [Via]