I haven't been down there in about 6 months, but the last time I went partying in Buckhead we went to Whiskey Blue (at the W Atlanta). Awesome location, especially in the dry months...high as hell prices...bring a vendor to pay for stuff.
I also enjoyed the hell out of Holeman and Finch, but that is a bit south of Buckhead. Good beers, but I think selection was limited.
Fogo de Chao has a nice bar, and awesome food, but not much of a beer selection.