Yeah, I know it’s everybodies favorite buzz word, but here’s some software that will try and free you from buying Windows Servers, Group Policies are good

http://www.nitrobit.com/GroupPolicy.html

To me, the idea behind the Open Source Enterprise is to reduce cost, improve flexibility & maintainability. It’s likely that there will always be a need for Windows desktops in most SMEs, unless it’s a clean sheet site & you can avoid getting locked in at the start. With tools like these, you should still be able to carry on reduing your Windows count.