Paul Graham has some great essays online that made up the content of his book: Hackers & Painters. One of my favorite posts is The Python Paradox, which presents something rather counterintuitive at first read:
"I'll call it the Python paradox: if a company chooses to write its software in a comparatively esoteric language, they'll be able to hire better programmers, because they'll attract only those who cared enough to learn it. And for programmers the paradox is even more pronounced: the language to learn, if you want to get a good job, is a language that people don't learn merely to get a job.
This concept may be a little scary to some. Learning an esoteric language improves your chances at getting a "good" job? (presumably "good" meaning one you like) But what about all the recruiters salivating for Java/JEE and .NET programmers?
"People don't learn Python because it will get them a job; they learn it because they genuinely like to program and aren't satisfied with the languages they already know."
.. and there lies the paradox. If you don't know an esoteric language, or one that is not considered mainstream Enterprise, you can't learn one just to land a job. You must already happen to enjoy programming enough to seek it on your own.