The cost of living is low but that's due to Georgia being 10 years behind in development compared to other states. I used to rent a studio apartment for less than $300 and it wasn't crappy.
There are a lot of black people in Georgia (especially in ATL, it isn't called chocolate city for nothing) so you might experience a small case of culture shock. You're going to see a lot interracial couples and for the most people it isn't a big deal. Good ol boys are alive and well but you'll have to go looking for them around ATL.
Southern hospitality is real, get used to people saying hello and giving you a legit smile. On the other hand ATL is the NYC of the south so it might be slightly muted there.
Churches are a dime a dozen and there are some cult like ones but you'll be able to spot them easily.
The beard will get you weird looks but you're good other wise.
For some reason Georgia is starting to harder and longer winters, ATL just got hit by a snow storm that shut the city down. You're going to melt in the summer and gnats are going to eat you alive.
ATL has team for all of the popular pro sports so you'll have someone to root for. Check out five points for some night life. City-data is a great place to get info about where to live and where to stay clear of.
Hope that helps.