@caperson67
Up until recently, I would make the same arguement as you about Linux. I'm a die hard open source nut, and look for every avenue to put Linux or open source solutions in our infrasturcture. But, the bummer was that, while LDAP can manage access to folders and files, it cannot manage workstations and policies like AD. However, Samba is developing Samba4 that will handle all of this for us. It is still in alpha release, and no release date has been set, but it is in the works. You can read about it here
http://wiki.samba.org/index.php/Samba4.
I'm not advocating jumping off the AD wagon yet. Just bringing it up so you can keep your options Open