We spent a week in Buenos Aires and would go back in a heartbeat because a week is nowhere near enough time. On the plane ride there, we were lucky enough to have sat next to a young local guy who gave us an overwhelming amount of insider info - where to eat, where to shop, where and what to drink, and where to see Tango.
We ended up booking an evening from an advert we found that included a nice meal (with beef, of course), endless Argentinian wine, and a very memorable Tango show. The cost was very reasonable and what impressed me most was - and I don't mean to cheapen the experience - was that, in Buenos Aires, even side stage Tango is amazing. It's much like Las Vegas in that way.
We didn't pay for top billing that night and we even wandered down to the La Boca district to watch Tango on the street and it was all truly captivating.....passionate....elegant.