If your company connects branch offices to the main office, you can use the new ISA Server 2004 Cache-Savings Calculator to help you model the potential savings from deploying ISA Server 2004 instead of upgrading network bandwidth.
While you are in branch office planning mode, check out the Branch Office Infrastructure Solution. It uses virtualization technologies and includes tools for automating the creation of virtual machines, among lots of other good stuff.
From the download page: "The Branch Office Infrastructure Solution (BOIS) deliverables provide conceptual information to facilitate the definition and deployment of a streamlined branch office infrastructure solution that provides a comprehensive set of core IT infrastructure services based on the Microsoft® Windows Server™ 2003 operating system. The BOIS deliverables also include prescriptive guidance and best practices for implementing a complete, lab-validated single-server solution for the branch office using automated deployment tools. The automation tools are part of this download and are configurable for individual branch office deployments."
And don't forget to read eileen's blog post about using MOM 2005 to monitor Active Directory across slow links.