I don't have that much experience with any of those, but I think C++ is still the most versatile. Python is useful in certain situations I think, and for those situations it may be easier to use than C++, but I think it's easy enough that if you knew C++ you could pick up Python even more quickly.

Learning a second language is generally way easier than the first, because a lot of the underlying fundamentals are similar if not exactly the same, and once you get those concepts down it's just a matter of learning new syntax and semantics that language uses to do the things you're already familiar with from the other languages you know. Nonetheless, there are certainly other differences that will likely make it challenging.

Might help if you gave us some idea of what you might want to program--simple applications? Complex applications? Video games?

Still might want some input from someone who knows more on the subject. Discounting XHTML and CSS (which really don't count as programming languages--if you're using them as the metric by which you judge the potential difficulty of learning a new language, you might want to rethink) I only know PHP, which barely counts either.