In Vancouver, we only drink pop.
In texas the default is "Dr.Pepper"I believe the thought that people in the southern US call it Coke is because it's the most common soda offered. My experience is that people use the product's name Coke, Pepsi, Sprite. People are so used to using Coke, because of how common it is, they will ask for it out of habit at restaurants that don't offer it.
The farther you get from Atlanta the less common Coke becomes. Since Dr. Pepper was invented in Texas I would expect to see something similar. Dr. Pepper's popularity wanes as you move away. Here in Georgia it's an alternative. Pizza Hut and Taco Bell have Pepsi not Coke. Most every other fast food restaurant has Coke, but you can get Dr. Pepper at all of them.In texas the default is "Dr.Pepper"

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.