Which of these languages...

is the most worth learning, in your opinion, and why?

Russian, Turkish, Urdu, Punjabi, Korean, Hindi, Arabic, Chinese, Bengali.

Additionally, which countries that speak these languages are pleasant and which are shitty?

I might obtain a scholarship to study one of these languages abroad. I am American, with paltry knowledge of French and Japanese. For any language, I would be mostly interested in the wealth of literature that would be opened up to me. A language and culture very much unlike my own is a plus.