If the term
easter egg is more loosely defined as "hidden surprise concealed in software", then I believe that Windows XP (Build 2600) does have at least one treat waiting for the user -- especially if that user is a
music lover.
The ambient techno looped song that plays during the end of the operating system's install process is hidden in an obscure directory, never to be played again (unless it is found by the user).
Oddly, the file is called at least two different names, depending on the Windows XP installation: "Microsoft - Windows Welcome Music.wma" (which is the filename on my machine), or "title.wma". It is 2.5Mb in size, and is hidden in:
C:\WINDOWS\system32\oobe\images\
I've been unable to discover (yet) the composer of the piece, or any other information on its creation. Is this a hidden Eno gem? Given Brian Eno's prior engagement in the audio frills of older versions of Microsoft Windows, it is possible.
It is a very nice composition, soothing and effervescent, and in this noder's opinion, well worth finding and playing.
Noder 1010011010 agrees that it is a nice track, and adds the info that the file is 5m24s in playing time, and is encoded at 64Kbps.