[Prikrutil]

It would be very tempting for me just to answer "yes, it's very important" or "not, it doesn't matter at all" with appropriate arguments, but I don't think any of those answers could reflect in full what I actually think.

It's very important. Your effectiveness as a programmer depends on which languages you can use when solving problems. Also how easy it will be to extend your program in the future depends (among other things) on which language you've chosen.

If you want a language to reflect your thoughts as directly as possible you may want to use one of the problem-oriented languages (R for statistics, Erlang for fault-toleranse servers, Python for scripts etc).

I think that language matters, because the right chosen one usually increases your efficiency when it comes to writing a specific applicatoin.

It doesn't matter.

In short: it doesn't matter how sharp a sword in your hand is if you are a master of swords.

My current languages-to-learn list is: [Erlang | [Haskell, OCaml, Lisp, Python, R]]