Last night I went to Milion in Recoleta. This place is swanky. It's a an entire restored turn of the century French house, grand, expansive and gorgeous, oozing sophistication. It's a restaurant and a bar. I enjoyed a delicious mojito in the bar area upstairs. Not cheap at 25 pesos but worth it for the atmosphere.
The only downside was that later in the evening it seemed to morph into the US embassy dining hall and we were suddenly surrounded by inexplicably loud nasal chatter. We had to move to a different part of the bar to escape.