Which graphical environment (MFC, ATL, QT etc.) should I concentrate on, in order to be more employable? I don't want to spend months learning something only to discover that "no one" really use this or this really sucks, and "all" pros are using only such and such.
Compare the number of jobs on various employment web sites for each technology you are asking. I believe MFC is still in most demand, but may be wrong.