What are you doing while in town?
If you're there for the aquarium, college football hall of fame, CNN, World of Coke then you may want to stay downtown. The Westin downtown is kind of cool, though it could be pricey. You will want to avoid the area around the Fox Theater past dusk.
We like the Buckhead area and when trying to $ave have done well with Priceline... usually getting the Hyatt Regency or JW Marriott (we prefer the former). We also have access to a hotel program that gets us to the Inter Continental. We like that as well, but will run you some more coin. A couple of nice malls and restaurants nearby, mostly walkable. Easy access to MARTA if you need to get downtown. Parking is typically $20/night.
You can stay a bit further out for a bit less. The Perimeter area offers lodging, shops, restaurants and a MARTA station as well.
I've never stayed in these locations with a youngster in tow.