I used to live in northwest GA, less than an hour south of Chattanooga.
The Hamilton Place mall area has a LOT of hotel and dining options. It's off I-75 at exit 5, IIRC. Exit 1 in Tennessee also has some hotels and dining, but the Hamilton Place area is nicer, IMO.
If you go past Chattanooga into GA, Dalton is about 20 minutes south and Calhoun (my old home town

) is about 20 minutes past that. The Walnut Avenue exit for Dalton (they changed the exit numbers, but it's the first exit past Dalton College, which you'll pass on your right) and the Highway 53 exit for Calhoun are probably the best bets for hotels and dining.
There's also a rest stop in GA right over the state line and another between Dalton and Calhoun.
Depending on the time of day you're entering GA and how tired you may or may not be, I'd almost recommend getting past Atlanta if you want to stop for the night. 45 miles south of Calhoun is Kennesaw/Marietta, and you're definitely in the Atlanta suburbs then. If you stop north of Atlanta on a weekday, keep in mind you'll have Atlanta traffic to contend with in the morning.
If you decide to brave the Atlanta traffic in the morning, well .. godspeed

and make sure you take the HOV lane through downtown because the Perimeter I-285 can be as bad as downtown at times.