Bellagamba dos in Caballito (Av. Gaona 1327) has the same happy feeling as nr. 1 in Rivadavia, perhaps caused by those marvellously cheap beers and tasty empanadas, but it's larger and has a small patio which is open during the day. They're also working on a second floor, where smoking will be allowed and probably encouraged.
Pool San Bernardo, in Corrientes not far from Malabia at subte B, is probably the most perfect bar in the universe. Not only is the beer cheap and plentiful, it also has a lot of pool tables, entertaining senior citizens and, alas!, ping pong tables in the smoking area for those of us who take sports seriously.
Picture 1 is from the ladies' room, thanks to MJ for the research.