From the sound of it, you seem to be saying “There’s so many coders in javascript, everything’s already been written in it that CAN be.” And that’s just silly.
How about this, though – I am pretty fluent in well more than a dozen programming languages. Which one is best depends entirely on the final intent, but one thing remains consistent – algorithms and design patterns. That is where many programmers are weaker, and where a true “master coder” can distinguish themselves.
Many of the questions that pop up, either on the JS forum or here or on other language boards (Ruby, Python, Perl, PHP) have to do with “Help, I’ve gotten tangled in the mire of logic and I can’t get out!” Learn to understand the logic that underlies the code, and the language becomes secondary.
Every language has some sort of branching system, some sort of looping mechanism, and some kinds of data structures. But the patterns to solving the logic is completely separate from all that, and applies to pretty much every language.
I see it as “big picture / detail” view. Start somewhere, learning the details, sure – but keep in mind the big picture view.
I’m not saying to learn all the languages you can, but learn to think outside whatever languages you choose, and into the level of logic and data structure.
Now, to answer your question, what are you curious about? Do you want to learn to code device drivers? Some languages excel at that. Do you want to create useful data feeds for web apps? Another set of languages are really good at that.
Find out your interest, and then find a language to fit that. Not the other way 'round.