Yes I am aware of the security issues of both operating systems. That is beside my point. Hell, if your looking for an extremely secure system go with OpenBSD default (and somewhat useless) install, yes they audit every single line of code so you can rest easy. However, there are *still* some features for corporate desktop management that windows server holds over linux/samba combinations and friends.

AD is not fully LDAP combatible, yes, but I am concerned with all the features and utilities that come with AD. If you've ever seen group policy objects in action, you'll know why they are so crucial. Also, there is no good replacement software for RIS and pushing patches/applications over Active Directory.

The only other option is to turn the corporate desktop in the direction of linux. Redhat is working on this, but its a way off. Users dont want to switch their desktop's they are so used to.