SA/CA definitely has it perks. If you can get even basic Spanish, you're opening a lot of doors for yourself.
I've got some timezone-sensitivty with my nomad life so South America has been my spot for the last 3 years (here for North American winters, NA for summer).
I'm in Quito right now. Great city. Cheap. My 1br/2ba AirBnb in the heart of town is $40/nt and even cheaper because I'm staying 2 weeks. I plan on checking out Cuenca, Montanita and Banos before I leave Ecuador, so I can give updates later on that.
Last year, I did Costa Rica & Colombia. @TProphet is absolutely right about Costa Rica. Same $$ of living as most places in anymore, more than some spots even.
Chile is good. Cost of living is a bit higher but it's very, very stable. Great internet everyone. I found Santiago to be a bit boring, but Valpariso on the coast is one of the cooler places you'll find.
Buenos Aires — yes, not the best internet. Definitely work-able though. But amazing, sprawling city. Lots to do. Lots to see. Beautiful people. Steak & wine for dinner. You NEED to bring American $$ down there for the exchange though, the black market is almost 2x the value. A little shady, but worth it no matter what.
Medellin — probably my top recommendation for any Nomad looking to get to SA. Beautiful, beautiful place right in teh mountains. The drive from the airport into the city alone is worth a trip down there. Yes, it has a violent past, and some problems, but there are nice neighborhoods that really don't see that. You can always cab places and it's super cheap. But the city is a renaissance, lots of nomads, coffee shops, juice bars, organic spots, etc... Absolutely recommended in my book.
Hope that helps!