Pop
It's more of a midwestern term, and I'm perfectly ok with that.
Soda sounds too snobby to me.
Now then, calling every carbonated soft drink "Coke", that's just stupid.
I have called soda "soda" for 25 of the 26 years that I've lived. The [i]one[/i] year that I made an exception was when I lived in a backwater rural town in New York that thought soda was called "pop" for some asinine reason.
I live in the south so Coke and Pepsi can be used for any soft drink.
Have a Sprite? “Hey, grab me my Coke(and/or Pepsi) over thur.”
And you cannot forget Sodie-Pop