I live in the south, myself. For the most part people use the word "soda" more often. "Pop" is kind of old fashioned, and as some people have already commented, "coke" refers primarily to those dark sodas similar to Coca-Cola. At least down here, someone would be more apt to say, "Pass me the soda, please." If there are several drinks available, then they would ask for the particular name There may well be regional differences though, as you commented, Lena.