Try
Casa bar for cocktails, televised international sport and meeting English speakers. There are some great restaurants opposite, and a good nightclub, Shamrock 2 blocks away.
El Alamo - for beer in pitchers, US sport, sardinesque most nights.
Jack the Ripper for a more pubby atmosphere and, oddly enough, better to meet locals.
Gran bar Danzon the wine list itself is a book on Argentine viticulture, good cocktails, suited-up crowd.
Bullers Brew pub, good nibbles and strong honey beer. Happy hour good value.
Shamrock begins with after-office bar upstairs, debunks somewhat symbolically downstairs through blackout curtains to an all night electronica rave once the short hours chime.
Spot bar -I haven't been but have heard it is a sociable place. Good to meet people.
If you are spending any real amount of time in Recoleta and want to meet people, try joining some clubs. It is the aristocratic barrio and hosts a wealth of private members clubs, always happy to host a foreigner. Do not let the words Syrian diners club or Jewish Orthodox society put you off, they are usually non discerning and good for socialising.