There are plenty of excellent choices, depending greatly on how far south you want to go before stopping.
The first place I'd stop south of Atlanta is Locust Grove, exit 212, where there is a nice and fairly new Comfort Suites, and another Comfort Suites in Byron, exit 149, just south of Macon. We stayed in the Byron location a few months ago, so I can personally recommend it.
Valdosta has a nice Country Inn & Suites, and yet another Comfort Suites, among most of the major chains. I've stayed in both within the past year, and either would be a fine choice. If you want to make it as far south as Florida, try the also fairly new Fairfield Inn at Lake City.
Everything I've mentioned serves a complimentary breakfast.