Ask HN: What programming language do I use?

Depends on what you're doing. Right tool for the job and all that.

C, C++, Java and PHP are popular (according to the Tiobe index). The last 3 can teach you some OOP if you're not already familiar with it.

If you're interested in functional programming, you can learn some stuff from Lisp, F#, OCaml, Haskell

Common ones are Native mobile apps: Java (Android), Objective-C (iPhone) Web apps: Python, Ruby, PHP, Javascript

already into php, js (and jquery), actionscript with mxml in flex and flashbuilder. Programming not about apps either. What i meant was core programming, to execute "complex algorithms".

Go deeper with Java.Super extensive Java libraries will assist you much in constructing complex algorithm.

i would go for golang, python, d (learning golang at freetime right now)

Golang. Is it fully developed. Plus, while learning, one requires an extensive developer community, wjich might be another hindrance.