The best programming language to learn is whatever your friends are using. There are a lot of benefits to collaborating with someone else and sharing code. If you're flying solo I would recommend the following progression:
Python ~ Easy to learn. Simple intuitive syntax. Very readable, it's almost pseudo-code. Large base of supporting libraries. Well suited for smaller projects.
C++ ~ Powerful, feature rich, complicated. Allows you to access memory directly and do all sort of other things that you should understand how they work, but probably shouldn't do. It's also very efficient and good for use in larger collaborative projects.
A personal interest language ~ Interested in A.I.? Go learn Lisp or Scheme. Like operating systems? Go learn C. Like hardware? Learn some assembly.
Once you've picked up about 4-5 core languages I'd suggest stopping. Breadth is important to get a good overview of the domain, but depth makes you much more efficient. Let your career drive further learning at that point.