Now Ubuntu are stable enough to use it in enterprise, but it can not replace Windows because of lack Active Directory features. Main of AD feature is admin can configure all network from ONE server, and all configuration stores in ONE place and have the same userID for all network.
Ubuntu can do the same but it need to have common configuration repository and main programs must get config from this repo.
It is hard to change all software in Ubuntu to use common config-API, but Canonical can change their own soft (Bazaar, etc). Then prepare soft that can configure it.
This will be great step towards usability and admin frendship. Also this will add marketing points to Ubuntu, because neither Windows not other linux distro (RHEL, etc) have same functionality. SuSE have Yast, but it is not the same.
Ubuntu and Canonical as a big Linux player can begin this great task, and help Open Source projects create ONE configuration API and move to using it.
May be you should look at gconf first and another tools next. And begin to migrate Cannonical own products to this common conf API, then help other projects.
This IDEA will easily fix
http://brainstorm.ubuntu.com/idea/68/ and so on.