Lockheed is a horrible example too because they have extensive classified operations (their support costs for email within classified projects probably exceed 7.5mm alone), and because Lockheed IS&GS is a major contractor for outsourced IT services.

I think the Gartner figure was something on the order of $500-1000/yr per employee for messaging in large high tech businesses. A lot of that is IT staff, and all the other systems for security and compliance. Email is one of the big apps within enterprise.