[kyllo]

There's absolutely no reason you can't be fluent in JS, Python and Ruby. Just try Python for your next project, then maybe try Ruby for the one after that. Or perhaps a functional language like Clojure or Haskell. Each successive language you learn will take about half as long as the last one, because you've accumulated the concepts and it's just learning more syntax.

Node may turn out to be a fad, so don't hitch your wagon to it fully. To be a good (web) developer you are often going to need to learn new languages and frameworks as the tech landscape changes.