Out of ATL, jump ship to AirTran for direct flights on their routes and stay on Delta for everything else. Their stair-step down model will give AirTran more time to grow with the 100 new planes they just ordered.

Also, contact AirTran's special member services desk. If you send in your Delta info they should match your elite status with lifetime elite. I'm not sure but it's worth it since you get unlimited upgrades from coach B/Y fares to business class. All other fares as an elite you can upgrade for $35 or 1/4 of free ticket (4000 mile equivalent).