I live on the edge of the pop-vs-soda line in the northeast (map). I grew up in western PA using "pop" colloquially. Now that I'm in central NY I've caught myself using "soda" a few times. I only use "soft drink" in its proper meaning, referring to the entire category of nonalcoholic beverages - that is, I see it written on menus and understand it as such, but I never say it because I either want pop or something else.