In case you are curious what it is like to be in charge of Security for IT at Microsoft, you get to deal with an environment where there are:
Microsoft IT (MSIT) has just released a white paper, presentation, and webcast covering how we have used Windows Server 2008 to improve our network security. You can read the paper online here: http://technet.microsoft.com/en-us/library/cc512829.aspx, but it is a great look at our implementation of Network Access Protection, Server and Domain isolation, IPSec, and other technologies to secure the network (while leaving it quite usable).
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Technical White Paper
PowerPoint Presentation
IT Pro Webcast