What's the price of a global variable?
Loss of access control. (Also violation of dogma.... j/k)
Globals can be reached by parts of the program that have no business reaching them and can result in serious design problems later on. It's a matter of whether or not you're working with people that can't handle the responsibility. Sadly this is a lot of people, from what I hear. Once things get complicated it can become nearly impossible to have reasonable state expectations for something with global accessibility.
That's a good article you got there, Hodge.