The simple answer is I am using
Windows XP Professional Version 2003 with the NT Kernal 5.2
More stabler and with all uptodate security fixes.
People who use Server 2003 as a Server, that's fine. But for the others (basically the majority) running it as XP Professional Version 2003 is cool too.
Here is what another guy says at Neowin:
As far as i am concern i think Windows Server 2003 is
WinXP + SP2 plus a lot of Server Features and components.
The bottom line is that Both OS base should be the same. However. Server 2003 seems to use NT 5.2 Keneral rather than 5.1 as WinXP. Since there aren't much information publicaly avalible on what has change that i will ignore for the time being.
And most of the sever features in Server 2003 can disable easily. While features that a workstation user want can be tuned back on easily as well.
Therefore by tuning Server 2003 into a workstation they are getting a better/ stableier/ and newer OS to use. Without continue downloading 10s of update or applying Services Pack to XP or slip streaming their XP.
However i do agree that turning a sever product into desktop use may not be the best idea. As far as complablity are concern i am not sure will it run program as smooth as XP does when running old legency applications.