[jetti]

The problem is F# has arguably the best tool chain out of all of the languages you listed. Hell, I still have problems getting Scala to work with Netbeans 7.1 and I'm not sure of any IDE (for windows at least) for ML, Haskell or OCaml.

[spacemanaki]

You may be right, but on the other hand F#'s toolchain isn't that hot on OS X and Linux (being facetious, but I'm half-serious). Anyway I was really only talking about the presence of a "first-class" REPL.