Corporate bodies, such as businesses and the government, have traditionally been rather slow when it comes to adopting new software and technologies. This is generally for security purposes, and because they don't see the point in upgrading from something that works. This frame of mind is not going to change any time soon; Ars Technica is reporting that the US Army is going to finally be fully upgraded to Windows Vista and Office 2007 by the end of 2009, despite Windows 7 quickly approaching.
At the moment, Ars Technica believes that about half of the Army computers are running Office 2007, and 13% are powered by Vista. Marcus D. Good, who is the chief of the Army's Information Technology Systems Support Division, has stated, "The Army has been testing Vista since its release and has run it through the Army Golden Master program. The Army Golden Master program is responsible for the release of the Army standard baseline configurations for commonly used computing environments within the Army Enterprise Infrastructure, the team responsible for making sure applications that ran on XP will run on Vista."
It's unclear how long it will take the Army to make the move from Vista and Office 2007 to Windows 7 and Office 2010 when they are released, but since the changeover will only be fully complete this year, expect it to take a rather long time. It's not a bad thing, though; the Army is serious business, and they need to be 100% certain that their computers are secure and safe. Previews of Vista for members of the Army are available here and here, to help them get used to it, as well as more efficient.