Uhm, although I admit Haskell is a powerful language, there are quite a few things that Haskell can't express as clearly as Scala. E.g. Haskell can't express nominal subtyping.
Monad m => Int -> m Bool
Haskell actually has whole program type inference (unlike Scala, which only does local inference), so fold/map will always return the right type as well, but you also get to not have to put types anywhere if you don't want to (including function signatures).
Scala's main advantage over Haskell is being able to call into Java.
+ a superior module system + better type classes (no global namespace)
But yes, if running on the JVM is no option, Haskell is a serious contender