Ask HN: In what language should I invest my time?

A couple years ago I was a C++ dev; I then switched to Python (and really enjoyed it for a while), but I'm getting a bit tired of it. So, I'm searching a new language/community/framework to invest my time in.. I'm thinking something between node, clojure, Qi, or Objective-C(With all the iphone development obviously)..

What do you think? (Note that I've already read a bit on these languages and few others)