In and around the airport--very ghetto but what major city with a very busy airport isn't? You couldn't pay me to live in Riverdale.
Suburbs up to the north are a different story--very nice! Marietta, Vinings, Alpharetta, Roswell, etc..I'm in Vinings and it's a 20 min shot to the parking lot.
Newnan and Peachtree City to the South are great too.