One of the main things i've been waiting for in the Longhorn betas have been enhancements to Active Directory. Not much has been done thus far but some of the changes should be showing up in beta 3. I have been able to discover some new Longhorn DCPROMO options that are pretty interesting though. You will now see the options below within DCPROMO:
Specifies that during the domain controller installation, the domain controller will also be configured to be a DNS server, global catalog server, or RODC.
Specifies the site in which the domain controller should be installed.
Set functional levels
Sets the domain and forest functional level during the installation of a new domain or forest.
Password Replication Policy
Specifies which account passwords to allow or deny from being cached on an RODC. This page appears only if the UseAdvanced mode installation check box is selected.
DNS delegation creation
Provides a default option to create a DNS delegation based on the type of domain controller installation (as specified on the Choose a Deployment Configuration page) and the DNS environment.
It sure is nice that a lot of these options are included within DCPROMO especially for small to medium size companies that may use some of these options for tweaking. However I don't see larger companies taking advantage of these because of the all the hoopla they have to jump through to make changes.