One thing that you do learn from using different languages (if you are paying attention anyway) is that they have different strengths and weaknesses and that there is no one language that you would wish to use for all tasks.

And this is the same view that I have about knowing one or possibly multiple languages. Each have their own style that fit better with specific tasks. If anything I believe that your fluency of one or more languages classifies you as a programmer. Finding new or "cool" uses for a particular language. I think it all rests on skill and usability soley on the person's end.