I agree Krell. I started life in New York City where we called it soda. When we moved to the San Fernando Valley, when I was 8, it was called soft drink. My best friend's mother, who was from Nebraska, called it pop! Here, today, in Northern California, it is called soda. I suppose that the south may well have adopted the soda name by now...
Actually, as I grew up in NOLA, it was very rare, almost nonexistent. I think Pepsi had an uphill fight across much of the South. IIRC, the turning point was their ads appealing to the young.