We bought a GA Backpacker Guide book a couple of years ago and it is very helpful. It helps up pick places that will fit our schedule for that weekend. It is nice to have a lay of the land and tips on parking before you drive out to a new place.
The Georgia section of the Appalachian Trail is a hard yet fun trail to hike. So far I've done most of the Georgia section as well as up into the N.C. and Tenn. area too. It's a well used trail that can have some good views along the way.
another good hike is right by Panther Creek. If you go past the Sandy Bottoms camp grounds for 4-5 miles you will see a primitive camp site on the left. It is pretty hard to miss, it cuts off to the left and has a good parking area. If you cross the river, there is an old logging trail that winds up the mountain. It's a good hike and you get some great views from the top.