Weighing in under the me too banner. FoxtrotUniform is correct. Balance above all or as I mean a generalist.

You have to know what is going on in the industry. As things change all the time and *Shock* even Perl might get replaced. Knowing many things/languages will insolate you from the downturns of business. If there are layoffs and you know multiple languages and the other guy was a specialist in Perl. I would bet they would keep you.

I once made the mistake of specialising on a mainframe and mastering a scripting language as well as the OS. Well that computer is no longer made and nobody cares that I was really good at it.

Balance