In order to continue to be effective in my job as a code monkey, I constantly need to learn new things. That could either be enhancing my understanding of the technologies I already use or learning new technologies. Which ever it is, I'm always reading a book or a web site just to keep up.
I try to avoid getting bogged down learning dead end stuff which will probably mean that I am not learning something I really should be learning. Dead ends are unlikely to reward me for the effort and will probably result in my re-writing a substantial amount of code.
My present major concern is the Windows desktop platform. Will it survive this decade in a recognisable form? I have a lot of coding invested in that platform. I'm hearing noises about platforms supporting applications in JavaScript so maybe I am sitting pretty with my existing skill base. Maybe I need to put some real effort into learning Java despite of the fact that I have seen that it isn't nearly as platform neutral as originally intended by Sun. What about Dart?
If OS vendors are turning to JavaScript, will Dart ever do that? Right now I would not learn Dart. But I never rule such things out. Ultimately, the reason that I am skilled in JavaScript now is its universal and reasonably uniform browser support. And provided you avoid using the crap features, its a reasonable language to work in.
The real problem in web development is the awful DOM API. If "JavaScript Harmony" helps there, I will most definitely be learning more.