Haskell forces you to think in a certain way. So if you want to learn about functional programming, then when you're searching for programming examples all those examples will be in a functional style. You can then apply those styles to Scala or F#. Personally I'd lean towards Scala (on the back of Spark) - there's the Coursera Scala Functional Programming course [1] which will give you a good start.

  [1]: https://www.coursera.org/specializations/scala