Obama Inauguration Protected by Windows XP

Now that Obama is the 44th President of the U.S., the security measures that were in place to ensure a smooth inauguration will still continue to be in force for some time.
Although all the security agencies involved in today's event won't be out in full force every day, the security for Obama's new presidency still demands a certain level of awareness.
What better way to ensure that everything goes smoothly than to use Windows XP on FBI intelligence machines.
It looks like the FBI is reluctant to move to Windows Vista for laptops.
The FBI was out in force today, with a list of high-tech anti-threat technologies, including a bomb vessel designed to contain a live bomb, and even allow it to explode if necessary. The FBI also had a mobile command center on site, where it coordinates and organizes on-site agents. Able to execute all commands and observations, the mobile FBI command center is a big armored trailer with laptops and other computer equipment inside.
If you wanted to build a secure setup? What would you personally use for the ultimate security? Would Windows XP suffice? Or would you use something along the lines of Linux or BSD, or even Mac OS X Leopard? Do you think you can lock down a Windows system as hard as one based on *nix?