This thread has been very informative, and I have booked a trip for two and half weeks starting at the end of October.
When I was in Paris, I rented an apartment from an agency called ahparis.com. It worked out very well. I have seen some references in other forums to a similar agency in Buenos Aires called bytargentina.com. I am wondering if anyone here knows anything about it, or has other accommodation suggestions.
My inclination at this time is two take Spanish lessons for a couple of weeks (I'm not a novice, could do a a consumers guide to courses in Toronto, and have travelled in Bolivia for one month and to Mexico more than a dozen times). I will, of course, leave a little time for photography.