Well, I'm not actually "from" the midwest--I just lived there for 3 years while attending undergrad. But don't stop feelin' the love on that account! :)! I actually ALWAYS said "soda" before I moved to Cleveland, but then I was waiting tables while there, and for some reason people didn't understand what I was referring to when I said "soda". Conversations would go like this:
ME: "Hi, I'm Amanda; and I'll be taking care of you tonight. Can I get you guys something to drink? One of our freshly brewed beers, or a soda?"
Patron of 'Wallaby's Brewpub': "Err, no, I'd like a pop."
ME: "Clearly you are a freaking moron. Can you not grasp that 'soda' is a different word for the carbonated beverage you refer to as 'pop'? I will bring you a soda, but I will fill it with ice and too much syrup to punish you for your insubordination in questioning my linguistics."
Hence, I had no choice but to almost immediately switch over to "pop". Now that I'm back on the east coast, people look at me quizzically if I say "pop". I still do, though. And I have a friend from Pittsburgh who has switched to saying "soda" now that she's lived in Boston for 5 or so years; and she informed me that her peeps back home say "ooh, aren't WE all hoighty-toity!" if she says 'soda' instead of 'pop'.
Soda. Pop. Tonic. Coke. Just gimme a damn water! Can't we all just get along?
Oh, and yeah; I was listening to that Jewel CD at work on Friday. :)