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).
Technical White Paper
IT Pro Webcast