On Sun, Nov 2, 2008 at 2:19 AM, Haworth, Michael A. <Michael_Haworth@pas-technologies.com> wrote:
  there are multiple changes being considered on our network and (of course) most of them hinge on keeping or eliminating Windows as the Corporate OS.

You should stress to your supervisors that having a single "Corporate OS" locks you in and limits your options. 

The Internet is built on open protocols; the rule has always been that a protocol isn't ready for prime time until there are at least two independent software implementations that interoperate with each other as well as they do talking to themselves. Even when you don't have open source software, having open protocols gives you the ability to plug in a server running any OS.

So ask yourself if you really need the proprietary extensions that products like IIS use.  If you can turn those off, your users will not notice when you swap in a server running a different OS.