On his blog, Occasionally Sane, my friend Gnuvince tries to make a case for Python as a first programming language. He presents Python with a series of bullets, each giving a reason why Python is a good choice. While I think it may be a good choice pedagogically, it may not be a good pragmatic choice when someone is learning a programming language to find a job, as one of his reader commented.
But I think that betting on a sole language to base a programming career on is about as silly as someone mastering only the hammer looking for a construction job. His limited skills might not permit him to find a job, and even if he finds one, he may be confined to menial, unchallenging tasks. To push the tool analogy further, another workman that masters a wide array of tools will probably be more solicited and appreciated in his work-group, and be lead to more and more complex tasks, and more responsibilities within his group. Programming is very much the same: sometimes, it just takes something else than a hammer, and the right guy for the job is the guy that has the largest toolbox—the one with the Torx screwdriver set.