I would call to confirm, since some restaurants may do a special menu/brunch for Easter Sunday, but I've had real lunch at Parker's before on a weekend. Their steak salad is great. I'll bet they take reservations, too. And Iberian Pig's website says they are open Easter Sunday. Both are good and in Decatur. I think the usual brunch suspects in the general area--Watershed, Wahoo, Murphy's, Java Jive--will be mobbed.
The Iberian Pig
121 Sycamore Street, Decatur, GA 30030