In other words, don't leave the airport. Remember if you go out of the secure area, you will need to go through security again, that could take a good 15-30 minutes depending on the time and day of the week.

As far a NICE restaurants at the airport.... well I don't think any are great. Fast food for the most part, Chili's on concourse A (nice crown room beside it) ...
I'm sure others that spend more time in ATL than I do will give some more suggestions.