Following up my posting that map earlier, here are some specific favorites along your route and very near the highway:
Cincinnati: Camp Washington Chili
Chattanooga: Mojo Burrito in East Brainerd
northish Georgia: Character's BBQ in Adairsville - he was one of the featured stars on this season of BBQ Pitmasters. Phone first, though, he keeps very, very odd hours. (678) 481-6701
if you want a meat-and-three, and don't want to fight the gigantic armies of tourists at Mary Mac's in Atlanta, stop at Doug's Place in Emerson instead.
Kennesaw/Marietta: Big Shanty Smokehouse. Awesome.
Atlanta: JCT. Kitchen or Bocado, both on Howell Mill just a few traffic lights off the highway. Phone ahead for either. JCT's shrimp and grits are the best I've ever had.
Macon: Joe-Bear's & Sons. You will find better ribs elsewhere, but not, I believe, anywhere else in Georgia.
south of there: Smoakies.
I hope that you follow up and let us know where you ate!! Don't let that request be your only post.