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?

>>17
don't know about urdu or bengali but
http://upload.wikimedia.org/wikipedia/commons/0/06/OttomanEmpireIn1683.png

besides - the only reason you see in learning languages is sucking the cock of your potential future master better?