Before Windows Vista became Vista, its codename was "Longhorn". Do you remember the time? (and no, it's not a Michael Jackson reference).
Fortunately, the project was renamed to "Vista" because "Longhorn" sounds weird, like something ripped from a Spartacus movie.
If you are the proud owner of Windows XP or Server 2003, then you must have thought about changing its theme so that it resembles Vista.
Before you do so, why don't you use the Longhorn Transformation Pack and see what Microsoft had in mind back in 2005. It's certainly different and... who knows, you might even consider to permanently switch to it.
The Longhorn Transformation Pack will let you customize the operating system files, so that they will remind you of Longhorn.
Before performing the transformation though, it is highly recommended you restore original files, just to be on the safe side of things.
Modifications you can make affect the login, start button flag, progress dialog, toolbar button, and boot screen. You can also change system font, set toolbar to Longhorn style, and install Longhorn display pictures, screensaver, sidebar, visual styles, and wallpapers.
The result isn't that different from Vista, but it's calming somehow. You should give it a try if you're running on Windows XP or Server 2003 (SP1/SP2).
Read an in-depth analysis in our professional review for Longhorn Transformation Pack