I HAVE BEEN TO OVER 70 DIFFERENT COUNTRIES IN THE WORLD AND MY FAVORITE ONE (BY FAR) HAS BEEN NEW ZEALAND.
A relatively small country and easy to get around
Very Backpacker friendly
Very Diverse - Beautiful Beaches, rainforests, Southern Alps, fjords
Great food and wine
Very friendly and helpful residents
scenery, scenery, scenery
walking under a glacier and 1 hour later walking the beach
all of this and much much much more!
For me the first place would be any of the countries bordering Iguazu Falls in South America - maybe Argentina. Since I live in Italy and have a home in Colorado in the US, I've already seen a lot of Europe, North America and the Caribbean, but have never been to South America although I've been close enough to see the coast of Venezuela. I particularly like waterfalls and Iguazu looks spectacular. http://www.iguazuargentina.com/english/
I say Istanbul, it is a beautiful city. There are beaches and nice restaurants with scrumptious food. After that, You could tour some more around the country like Dat?a or Kapadokya
I freaking LOVED Machu Picchu and I have travelled a lot!!! I would recommend doing the Inca Trail and going through the Sungates at Machu Picchu!