Jonah Goldberg posted a link to this map over at the Corner. It told me what I already suspected. Across the South, people order Coke, not Soda, and definitely not Pop.
Red State culture in the South is rather homogenous. Add this to the list of reasons blue states hate us. Actually, the South, being the South, when one wants a soft drink, he will order it by name. When I go to a fast food place I order a Coke, Dr. Pepper, or Sprite. When I am accompanied by a Yankee, he orders a Soda or a Pop.
Order by name.
It just so happens that most everyone in the south orders Coke. Notice also Virginia. Purported to be a Southern State, Virginia is home to vast quantities of Pepsi drinkers — a repugnant lot of people.