I live in Atlanta, so here's advice for anyone who ends up here.
I'm a lover of barbecue ribs. The best pork ribs I've ever had in my life are at a place in Powder Springs, GA, called Johnny's. Their onion rings are also outstanding. I get emotional over Johnny's. There's also a really good barbecue place in Houston called Goode Company. For you Houstonians, it's on Kirby near the Rice Village.
I agree with Stormborn about Cracker Barrel. It's fine if you're on the road and want something better than fast food. Other than that, I don't usually even think of it. If you want good southern cooking of that sort, come down to Atlanta and look up a restaurant called Merrimack's. They close after lunch, but they're seriously good. If you go there on Sunday, make sure to get there before noon, or you'll have to wait a while for a table. Another good southern cooking place in Atlanta that stays open late is the OK Cafe. It's on the corner of West Paces Ferry Road and Highway 41, just off I-75.
If I'm looking for fast food, Chick Fil-A is by far the best as well as the fastest around. The best greasy diner, in my opinion, is Waffle House. If you're in Atlanta, you're rarely more than a stone's throw from a Waffle House, and they literally never close.
The best burgers in town, at least that I know of, are at the Vortex. There's one on Peachtree Road between 7th and 8th Street, and there's also one at Little Five Points on Moreland Avenue.
If I'm looking for something "foreign," I like French and I like Thai, but I'm not a fan of Indian, which I find too spicy, nor of Japanese, which is usually just too expensive for my budget. There's a good Chinese restaurant (not buffet) I used to go to called New Lucky China (a stereotypical name, I know), but I moved away from Kennesaw and don't go there any more.