My Two cents about Peru and Chile:
Peru: Cuzco is definitely the hottest spot in Peru, definitely go to Machu Picchu, make sure to climb up to Guaina Picchu, you get there by train from Cuzco.
The Nazca Lines are pretty amazing, you can do a helicopter ride or even small airplane, or you can see two of them from on top of a nearby mountain. Around that area you can also go sandboarding.
Another beautiful place to visit in Peru is Huaraz.
I am writing in short, you can do more research about these places online.
Lima, don't spend more than a day there, visit the Miraflores (downtown) area..
I remember flying Lan within Peru itself, Possibly flew AA to LIM.
Chile: Santiago is pretty boring. If you like skiing there are lots of resorts there and also there is an active vulcano somewhere in the south I believe.
Yep, in a nutshell..