Here's an interesting study I came across via this post on boing boing. "Generic names for soft drinks by county."
The key is small. blue="pop" red="coke" yellow="soda" green=other
I don't know how many conversations I've had on this topic... the next time generic names for a carbonated beverage comes up, I'll be sure to whip out this map.
I'm definitely a "soda" girl myself, although I think I grew up saying "soft drink." And come to think of it, my parents usually said/say "soft drink" too... maybe they chose it as a happy medium, seeing as my dad is from a "soda" county, and my mom is from a predominantly "pop" area.
I wonder what kind of trends you'd see in other English-speaking countries...