Scala

Scala has so many amazing tools in the language, and I think probably Haskell is in that same boat. There's a huge difference between making something easy for a casual user or a first time user and making it easy for someone who will be using this tool 40 hours a week all their career. The core ideas of immutability and side effect tracking will just boring Haskell will get you such a long way. And I find it so much a nicer programming experience than any other language. You don't need to go into astronaut stuff to get a lot of value.