I am old enough (late 50s) that settling down on just one programming language would not be a bad strategy if I was not a consultant. Maybe.
Over the last several years, I have been hoping to mostly just use Ruby for future work, but in the last 5 years almost half of my consulting jobs used a Lisp language (Common Lisp or Clojure) and the rest mostly Ruby, with some Java.
The Clojure language and libraries are very nice, and I am sure that problems with the development experience like poor stack traces (good work already in progress), etc. will get ironed out soon.
If you are an entrepreneur with your own product or web services based company, then pick one great language and use it until a better great language comes along.
For those of us who enjoy consulting, we will mostly use what best fits customers' needs.