There are fewer languages that are bad choices to learn then there are languages that are great choices to learn.
Sit on that for a while.
In other words, learning _any_ language is typically a great idea. You'll often hear people, me included, say that "Learning a new language will teach you different things". This is from the fairly intuitive of learning programming concepts fron other languages that aren't as prevalent as languages you've used in the past and applying them to languages where they're less prevalent yet they work and solve your problem in an alternate maybe even a more elegant way.
However, the way i see it, learning a new language is far more profound then learning new concepts. Learning new languages teach you new ways of thinking. Object oriented languages will teach you to think about the solutions to problems in terms of nouns in the forms of objects representing entities that are capable of performing actions (nouns that cary actions), Functional languages will teach you to approach problems in terms of actions that carry context (verbs that pass around state), Languages with strong DSL and macro support will teach you how to solve problems by creating new sub languages for the problem domain, Strongly typed languages will teach you the importance of type safety, Loosely typed languages may bite you in the ass if you're not careful and will make you appreciate them at the same time, Garbage collected languages will enable you to be more productive while taking a slight performance hit, Languages that make you manage your own memory allocations and deallocations will teach you discipline with the cost of failure of adhering to this discipline will be memory leaky software riddled with exploits.
Learn any language and _never_ ask if it's a bad choice. If some one tells you it's a bad choice, ignore them (that includes me too). Learn any language you want and i hope you learn many more and have many lulz and good times along the way.
"If art interprets our dreams, the computer executes them in the guise of programs!" - SICP
“If at first, the idea is not absurd, then there is no hope for it” - Albert Einstein