Best Answer - Chosen by Voters
Have you been to Argentina before? If not, don't miss Iguazu Falls - bit north of BA and hence off the route, but worth a 2-3 day round trip from BA.
I would definitely spend some time in Mendoza - even if you don't like red wine it has nice views of the Andes; if you do like red wine, some of the world's best Malbec is within easy and enjoyable cycling distance at some charming bodegas.
The bus journey from Mendoza to Santiago over and through the Andes is frankly spectacular as well (but watch your bags).
Given you have 2 weeks, you might want to stop in Cordoba as well - we didn't, but I hear it's a nice place - or head north from Mendoza towards Salta and the Bolivian border to see the salt flats.
Source(s):
A trip I took myself a couple of years ago.