I agree with DrPhil re Central and South America. Vietnam is also very beautiful. I spent 4 months there recently. However, I was working there, and was "looked after". If you're going by yourself (not part of a group) it might be a bit difficult getting off the beaten path unless you're an experienced traveller. That said, Vietnam is the most beautiful and photogenic country I've visited in Asia. And nice people.
If you decide to go there, let me know and I'll tell you about my favourite places.
John