I'm running Office 2003 at home, and my company has chosen to stay at that level. Seriously, shortly after 2003 the versions started getting weird. XML that previous versions could not open, and that violated someone else's patent. The idiotic "ribbon" for controls. Don't let me get started on how half-a**ed the ribbon is.
I even got it cheap: it's legitimate student and teacher edition, installable on up to three PCs in a household with a full-time student. Wonder what I will do when she graduates?