Last month I decided to go on walks every day at a nearby park and I am now getting more interested in going on longer hikes once in a while; really appreciate these posts, they are giving me ideas for my next trip.
Cochran Mill Park is really nice, there are three waterfalls there but one of them is a much longer hike. The park is pretty popular for mountain or gravel biking.
If you're looking for hikes around Atlanta, I always recommend the East Palisades trail. It's a nice hike along the river and there's the bamboo forest to see.