try Congo on Honduras between Godoy Cruz and hte railway tracks. If you go through the bar to the back garden it is very chilled out and a nice atmosphere. If you want to meet Argies try Post. A completely different crowd on Thames between Costa Rica and Nicaragua. Hollywood side try Unico. Have Fun.
Went to Antares last night. It's not really a bar though but they have great food and beer at very affordable prices. Make reservations early as it's very popular. Good place to start the night drinking in Palermo.