I am thinking about to learn new language or framework. Now I deal with C# and WPF, WCF, Winforms. I have some free time so I would like get new skills.
But I have dilema, start with some C++ framework (such as Platinum, Reason, Evocosm, ACF)
or try Python / python framework.
I you are on my place which possibility you choose?
I am 17 years student, I have basic skills in C++ (OOP, little with STL), with Python I haven’t any experience.
What would be your choice and why?
I recommend you to keep learning C++. Before you started looking for framework learn some popular search algorithm and try implement them. After that try implement some structures, like queues, list, stack, binary trees and some operation on them. Meanwhile play with I/O (for example, try write your stack to file and read it back to stack - in plain text and binary). 
It was my university tour on programming class. C++ is good choice because it is hard and multiparadigmats language so in future u will find much in common with other languages and you will be familiar with memory management system.
Start with some C++ framework or python