[kjksf]

It's really hard to say without knowing what your goal is.

If you know languages like C/Java/Python/Ruby, Haskell is much different, so you'll get exposed to radically different ways of thinking about programming.

Go is much closer to those traditional languages although it does add an uncommon (yet practical) way to do concurrent programming (goroutines/channels) that is worth learning about.

I know you don't care about real world applicability, but if it mattered, Go would be a better choice. It's explicitly designed as a practical language and in my opinion is a viable (if not superior in some ways) alternative to mainstream choices like Python or Ruby or Java for writing the most popular kinds of programs today: web applications.