RMS SP2, SharePoint 2007, and Exchange 2007
I think this one is killer one. With SPS 2007 one can centrally configure doc library with RMS applied, that means every doc created in this library would be RMS protected [encrypted and with per user rights]. Imagine doc library with Security Assessment for some project - each team member can access the web site and each one can download the doc but only those who actually has right to open it [say project lead only] will be able to see what is in it.
Exchange 2007 offers nice RMS story too.
· Installing Windows Rights Management Services with Service Pack 2 Step-by-Step Guide (http://go.microsoft.com/fwlink/?LinkId=76877); and
· Deploying Windows Rights Management Services with Microsoft Office SharePoint Server 2007 Step-by-Step Guide (http://go.microsoft.com/fwlink/?LinkId=76879).