My favorite mexican place is Agave - http://www.agaverestaurant.com/
The food is great, but the drinks are what's really good. If you're trying to just go out for some drinks / tapas type lounge spot go to the SoundTable. It's pretty trendy and classy, I saw Dam Funk there. My favorite brunch spot is Ria's Bluebird - http://riasbluebird.com/ If you go there on a Saturday at like 1pm you could very well see me hungover. It's so hipster'd out. There's like a prototype for ATL hipsters - they all wear tight black jeans and have tons of expensive looking tats and all work as waiters at Fellini's or some shit. Either way, I've only lived in Atlanta for a bit because I go to school there, this is the best I could do for you.