Should have been "11"
You put this whole thing together as if "Windows" was the only
solution. This is a fairly narrow-minded premise, given that both
Linux and OS X Server are at least as well suited to the task as
Windows is. Both come with:
THE most popular Web Server software already installed
And a sturdy Database package
And a proven Mail server
And a solid/flexible Chat server
And a sturdy Firewall
Did I miss anything? Oh, yes. Neither comes with a five-license
consideration. You can have four - or forty - XP systems
sprinkled about your office without having to buy a single extra
license for you server software.
The number one thing you should consider when designing a
small business network is how to get the best result for the
money you spend. Your focus misses this mark by a mile. Being
a platform bigot is ugly and wasteful. Any metric that requires
some or all your desktops use WinXP should not be considered
when it comes time to buy a server - and an office with more
than two desktops NEEDS at least one server! Every purchasing
decision needs to be justified - more so in a SOHO than in an
Enterprise - and "because I don't know any better" should be a
"terminal" answer.