Well, I'm not from Georgia, but a quick Google search brought up the Chattahoochee National Forest right in your backyard. That sounds like a great place to start, especially during Fall migration (right now)! 
Another bit of Googling brought up Kennesaw Mountain, which is near Atlanta.
Also you're right on the North Carolina border near the Appalacians, which is bristling with great sites. There's a series of books call the North Carolina Birding Trail (www.ncbirdingtrail.org). I bought the "Mountains" edition for a recent trip, and I highly reccomend it.