Well, I grew up in Queens (New York City), and we always said “soda.”
Here in Austin, Texas (Travis County), most people come from somewhere else, so one hears ALL the expressions for soft drinks. But native Texans always use “Coke” as a generic, all-purpose name for all carbonated drinks.
Hence, at a party, it’s common to hear exchanges like this
Host: You want a Coke?
Guest: Sure!
Host: What kind?
Guest: Pepsi.
I call it soda pop. That confuses everyone. 
Upstate NY here, and coke is OK. Soda is OK. Pop is a type of music. Buffalonians call it pop, and they don’t count anyway.
Around here it’s “soft drink.” Soda and “cocola” are pretty common also. Drink seems to be coming more popular. I’m guessing that’s due to a lot of fast food places having their drink machines set up so we serve ourselves so, when ordering at a fast food place people say, small, medium, large, 5 gallon drink and go fill it themselves.
The day I moved to Denver, after a lifetime on the East Coast, I went into a grocery store for a soda, and the very pretty checkout clerk asked me, “Pop in the sack?”
I stared at her dumbfounded, thinking “Damn! they’re friendly here,” before realizing that pop=soda and sack=bag.
Product genericide is not uncommon though. Got a cold? Get yourself some Kleenex. Headache? Take some Aspirin. And while you’re at it, why not xerox a copy of that report?
FWIW, in Canada – at least in Ontario, it’s always been Pop, though I’ve heard a few people refer to “Coke” in the generic.
The sad thing is that a lot of these places have free refills! So anybody with any sense orders a small and refills it enough to fill the 5 gallon gut they’re trailing behind.
Sort of like the leprechaun asking the Irishman what else he wanted for his second wish after ordering a bottomless mug of beer: “I’ll have another of these.”
Yes, but those are products for which there is not a wide difference between brands. One tissue is pretty much like another. Whether you make a copy using a Xerox machine or a Canon, the copy will still look like the original.
However, with the products in question in question in this thread, there is a wide variety between Coca-Cola and the other beverages that may be called Coke. I doubt you could easily tell a Xerox copy from a Canon or an HP, but you could quickly distinguish between Coca-Cola and Sprite, Dr. Pepper and Grape Fanta. They differ greatly from one another so it makes little since to use one as a generic term for all of them. The products are not interchangeable, so why should their names be?
Personally, I grew up using soda and have never lived anywhere where any other term is commonplace.
I just “popped” in to ask about “tonic”. It’s not the whole northeast; I use either “soda” or “soft drink”. But I’ve heard it used any number of times. I think that it is still used by some folks 40 years and older in Boston and surrounding cities (Cambridge, Somerville, etc.).
But pop? That’s just crazy talk! 
Genericide isn’t really about the differences in competing products though, nor is it necessarily (or entirely) from a lack of competing products. It usually comes about simply because one particular brand name in general is so pre-eminent in its field such that the vast majority of users of that type of product use that particular brand that its product name becomes synonymous with the product itself. Neither Xreox nor Coca-Cola lacked competition, they were just immensely popular, and people, being so used to referring to it by name, had simply begun to use it in reference to its relatives.
Old school video gamers were getting the same way back in the early 80s. Ask someone if they had an Atari and they’d like as not say, 'Yes, I did. It’s an Intellivision."
It’s soda to me any everyone I know, no surprise.
I grew up in Oregon, though, and we still called it soda, which doesn’t mesh with the map.
I grew up in Kansas City which is firmly in the “pop” area, but my parents are from St Louis, which is a small oasis of soda in the otherwise pop midwest.
So, I say soda.
I haven’t been in Oregon long enough to know what they say here. I’m still going to say soda.
Growing up in the Highlands… Fizzy drink
Moved to Glasgow…Ginger
Joined the royal Navy…Goffer
Moved to the States…Beer
Harrumph! Lifelong resident of the Boston area. “Tonic” is the word.
What’s that you say? Over 40? Um, well, er… 
Uh…I’m from Michigan but your post seems a bit angry to me. Have you not learned that language is never about making sense and is just developed by the people in certain areas?
My friend from Florida says when she wants Pepsi, she either says “Pepsi” or “Pepsi Coke”. Any other southerners heard that?
I call it Pop, but my Caliofornian wife has somewhat converted me to an occasional “soda”.
By the way, here is a dialect survey with many more questions.
Do you call it pop, soda or coke?
Australia: generic term = “soft drink”. Or, if you want to be specific, the actual brand name of the drink: “Coke”, “Pepsi” etc. I’ve not ever heard any differently.
…in Australia, that is…
Note to self: Keep doors locked when driving through green areas.
“Sodar”? Sounds like the ability to detect if someone drinks a lot of soda.