As a born and bred mid-Westerner, I say that it's POP!! Soda to me is soda water. After years of living in NJ, though, I do know what people here mean when they say they want a SODA!! I thoroughly humiliated my daughter on a trip to Chicago a few years ago when I stopped in the middle of the street, pointed to a sign in a restaurant window and started jumping up and down and yelling, "See, I told you it was POP!!""