Are you having fun because you switched to a statically typed language or are you having fun because you switched to a functional language? Would you be having less fun had you chosen Clojure?
I started a parallel implementation of a bunch of machine learning algorithms in Clojure and Scala. I figured the Clojure version would pull out ahead thanks to my previous lisp experience and lisp's history in that domain.
I was very surprised to discover that my Scala code was a lot easier to understand and maintain and had fewer bugs.
You know, I'm probably having fun because of both. I love the type system Haskell gives me for exploring a problem space without diving into a solution. I am enjoying working in a functional language because it forces me to work in really small pieces and slot them together. I try and do this in Perl too, of course, but it can sometimes be easier to just cargo cult some things and forget to come back to them.
I think what I enjoy most is the type system though, and the ability to make massive refactorings until stuff compiles. 9 times out of 10, things just work after that.
