Just saw this so may be too late. There are more cigar stores per square mile in Atlanta than anywhere else in the Southeast. But, only some are worth it.
Where are you staying ? If in Buckhead, La Casa de Tobacco is a nice, air conditioned cigar shop with a nice lounge area. A guy named Kevin will be working, so tell him Chip sent you in.
Dantana's is a sports bar in Buckhead with a cigar lounge in back. Have not been there in years, so can't give any firsthand rec.
If you want to browse a huge selection, Tobacco World in Marietta has about anything you can think of absent ISOM. This is Red's shop but he typically does not work on Sunday. Not close if you are staying in Buckhead or Midtown. (Presuming you are staying near the consulate office).
For beer selection, Taco Mac has a wide variety. They are all over town. If you are in Buckhead, Twin Peaks has nice scenery, cold beer and you can smoke on the patio (though it is hot as hell).
If you are downtown, there is a small shop near the aquarium, but I have not been in. I think the College Football Hall of Fame opened this weekend, so that could be worth a stop if you are a college football fan.
For fun, Virginia Highlands (VaHi) is a nice neighborhood to walk around. The Midtown area has Piedmont Park, and nearby is The Leaf, a cigar lounge with a liquor license. Their selection is poor, and I found the owners attitude showed me he did not want my business. Next door is the Independent, dive bar, but decent beer selection and you can smoke on the patio outside. If you are in Midtown, the Vortex is a fun place with a decent burger. Good beer selection.
Beer sales on Sunday after 12.
I am out of town this morning but flying back today. (Of course, that could mean I won't be back today). Hope this helps and PM me if you need more info.
