It's been fun watching this thread develop. Lots of good info.
Viajero, you're taking off to SCL? I am still heading to IBZ in late Aug/early Sept-- not yet sure if I will transit MAD or BCN. I'm forever a last minute planner.

I'll be at KLM/Spanair's mercy re. award availability.
About there being other places to visit before ASU: I've been to a number of places already-- after all, I am a Viajero Joven

. Excluding Guyana/Suriname/French Guyana, the major South American countries I have not yet visited are Chile (but ticketed in another trip), Uruguay, Paraguay, and Bolivia. I have been to EZE with my mom, and I will return sometime to do side trips--- that can be when I hit Colonia, check out spots away from BA (Gaucho, I'll keep your list

) and head up to Iguazu--- I hadn't thought of doing the bus all the way to GRU, but that sounds like an experience. All this will be when I have a week or two to travel. For this trip, though, I'm still working with like 4 days: Wed. night overnight to arrive Thurs., leave Monday PM to be at work Tues. AM. For that reason, I don't think I'll have time for side trips outside of the city. With SkyTeam partner miles, I have means to book EZE/SCL/GRU in my sleep-- it's the lesser traveled places only served by AA that are tricky, since I
never fly OneWorld.
I guess my thinking is that I'm young, and Argentina/Easter Island aren't going anywhere

so when I truly have time to experience them, I want to go and take my time. With this AA ticket, though, I have to use it by April, and before April, I can't be away from work for long. IBZ for a week is an exception-- making good on a 1 1/2 year old promise to my sister.
I hope that helps describe my situation a little better.....
Thanks for your help guys. I seriously appreciate it.