Latin America! The economic collapse in Venezuela and Argentina have made two of the traditionally pricier countries much more affordable. Colombia is a little more touristy than it used to be, but still remains firmly off the beaten track, other than Bogota, Medellin and Cartagena (but you should still go). Brazil is a little bit cheaper because the Chinese commodities market has gone tits up, though Sao Paolo and Rio are still charging first-world prices. Bolivia and Paraguay remain ass cheap.
The Pacific Coast still has its shit together, more or less, so you can go to Ecuador, Peru or Chile to recover in tourist-friendly comfort.
My recommendation, if you'll have more time than money, is to fly into San José, Costa Rica (almost always the cheapest flights in Central America from the USA), then wend your way down the Caribbean Coast to Bocas del Toro. From there, Ferry Xpress has new service to Cartagena. I've never done it, but it's cheaper and faster than the usual drunken boats you hook up in Panama City. If you fly straight into South America, definitely go for LAN or some other SA airline, not Delta or whatever, the points are not worth the extra cost.
Of course, that's assuming you want to skip Mexico and most of Central America. Fly into Cancún (usually cheaper than DF) and go south if you want to do all that.
"4 cylinder Camaro=communism" El Presidente
"You can smoke salmon but it's not quite the same as smoking heroin." nanuq