Man o man Fyre Sarge,
This is a tough can of worms to open. So much comes down to personal choice.
I'm from Texas so I usually need something that I can carry in HOT weather, probably very similar to South Georgia.
I would say .380 acp as a minimum. Don't let anyone tell you that a .380 with modern defense ammo is an inadequate mouse gun. I've personally seen patients come into the Emergency Department with .380 wounds and leave the E.D. by way of the coroner.
Good force on force training and proper shot placement make the difference. I'm sure that if you are a fireman/EMT you have seen the damage that most calibers can do.
I'm personally a fan of the many 9mm sub-compacts that are available today. I usually carry a Walther PPS in 9mm on most days. See
www.waltheramerica.com I also carry a 380 on occasion and even a full size 1911 or 357 magnum from time to time. Right now I just personally prefer a 9mm sub-compact for power/size/comfort/reliability.
Other great 9mm sub-compacts include the Springfield XD sub-compact, Glock 26, Rohrbaugh, Para PDA 9mm, Kahr Arms many 9mm models and many, many more. I would highly recommend finding a local range that has a large variety of guns that they will allow you to try (most ranges that offer training classes for concealed carry have loaners). Try out as many as you can and find the gun that you are the most comfortable with and the most proficient with. Then buy it and train, train and train some more.
Good luck and stay safe.