For me it's Japan. This is also one of the reasons, why I want to learn the language. The country is just so different from what I'm used to in Germany or I have experienced in Australia, where I lived for one year.
Israel
This is a matter of personal preference. there are 3 traits that attract me the most to different cultures:
1) very different from mine
2) well preserved/traditional/ancient
3) friendly to my own culture
Of the cultures that I'm very familiar with, Japanese and Thai are probably the most interesting to me.