First of all, Terminal E is the best terminal at the Atlanta airport. If you have a couple hours this is the place to hang out.
Next, make a POINT to eat at One Flew South. This is an upscale dining experience that I really recommend. The presentation is amazing and the service is excellent. This is a bit more pricey than the average airport restaurant but well worth it!
Schedule yourself an extra hour (which is always needed in Atlanta) and go enjoy yourself at One Flew South. You won't be disappointed!