Just because it's dominated by DL or AirTran (can they really dominate, though? ) doesn't mean you can't make a MR or find good fares. Other airlines still fly there, they just don't have the miles of gates that DL does.

Watch routes that AA may be trying to beat DL on; sure you'll have to connect through DFW or ORD, but that's kind of the idea for a MR, isn't it? Also watch fares from ATL to places that are not one-airline-dominated, such as LAX, SFO, WAS, NYC, etc. Chances are if DL lowers its fare on one or more routes, AA is likely to match. Or vice-versa. Just keep your eyes out, and maybe read some of the stickies at the top of this forum...

There's a lot of useful information in there. Yes, reading can be a PITA sometimes, but there's no substitute for knowing all the tricks yourself and being able to construct these runs without being at the mercy of other people, however friendly and helpful the other people may be.