This thread is probably long-dead, but I saw it and wanted to try the quiz. I'm
75% Standard American English (of course, in Linguistics we learned that there *is* no "Standard American English," but I won't go into that...)
20% Dixie
5% Yankee
0% everything else.

Seems reasonable to me. Got a Yankee father (Pennsylvania), live nominally in Dixie (Maryland is south of the Mason-Dixon line, but isn't usually considered to be part of the "South" nowadays), and a grandmother with a strong Bal'more accent.

I've always said "Coke," but I am conscious, in general, of who I'm talking to. In a restaurant I'd try to find out on the menu whether it's a Pepsi or Coke place, because I actually do prefer Coke to Pepsi and will order another drink if it's not a Coke place. If I want to be clear that I mean any sort of carbonated beverage, I generally say soft drink or soda.

Have you heard the joke about the person who wanted to make it clear they didn't care which side of the Coke/Pepsi wars a place was on, they just wanted whatever the place had, so they ordered a "dark, carbonated beverage," and the waitress laughed and asked if they wanted a long cylindrical plastic drinking object to go with it?