Floyd said:In all seriousness, if all you plan to run is one RO server on this machine, then either Linux or WinServer 2003 (I can't speak for XP) will do the job admirably. I'd look at it one of two ways.
a) You could opt for the O/S that you are most familiar with and can easily access.
-or-
b) If you'd like to learn a new O/S, choose your poison