I grew up (and still live in) Minnesota, so of course it has always been "Pop" for me.
I used to drive truck over the road and I very quickly learned the different terms people used for Soft Drinks in this wonderful country of ours. All it took was a few weird looks from waitresses in restaurants that I visited to realize just how stongly some people reacted if I said "Pop" in "Coke" or "Soda territory.
In my experience, I would say that this map does do a pretty good job of accurately displaying the regions which use the various terms.
My solution to the problem was to just use the term "soft drink". Everybody still knows what you are talking about, but yet you don't get any strange reactions. Also, if you notice the menus at national chain restaurants, they pretty much always use the term "soft drinks". I think this shows pretty clearly that this is the accepted generic term for these drinks.