Java script by far
i started out with python but i sucked at coding, i then learned java and did more advanced projects and truly felt like i understood programing form then on. then i started programing in JS for my website and liked it more. especially since all you need is a JS file and a browser which makes sharing my projects so much easier
Personally I am just getting started. Know Java but is learning Python and R to do more data-wrangling and statistics. To answer the question i think, as much in life, it depends on the goal.
I'm proficient in both C++ and C#, with some experience in hlsl shader programming. I'd have to say C# is my favourite so far; I'm not the biggest fan of memory management, so the garbage collection system in C# is greatly appreciated.