I work for a secure web host company and we mainly use linux or bsd operating systems for the services we provide. However we got into a debate over the relative merits of the different operating systems. I am aware most vulnerabilities on windows based systems come from the closed source apps they are running. but it came down to the client wanting to know one or the other of those 2. Does XP have any merits over 2K? and how come 2K has had 4 services packs while XP has required only 2. does XP offer anything 2k does not and vice versa.