Haskell for its unrelenting purity and take on laziness. Clojure because Rich Hickey's take on lisp and functional programming is beautiful in both concept and

Haskell for its unrelenting purity and take on laziness. Clojure because Rich Hickey's take on lisp and functional programming is beautiful in both concept and execution. Scala's type system (given its limitations from being on the jvm), traits, and pattern matching also are deserving of a mention.