i went to argentina for three months at the start of this year and i loved it, it beautiful, cheap and there is so much variety to see from the antarctic, the green of the pampas, and the tropical north you got it all ...
im going to go back there as well in a few months, id love to go to peru too for the old inca ruins and mexico for similar reasons as for the rest of the countries id like to see em all apart from colombia where there seems to be a lot of trouble atm..
i think central and south america is a beautiful place its just a shame there are so many ultra-poor people there..
oddly enough i know of a guy called Martin Gray he spent 12-18 months driving round sacred sites of south america in a campervan he would probably be your ideal companion..
hes doing a tour of sites of sacred greece next september with 25 others and there are still places left...youll find him if you search for 'sacred sites' on google...
what are all the countries youve travelled to ?