I second that. F* language from MS with dependent types, and compiles to F# and OCaml. I finally gave MS Visual Studio CE a try, and I am blown away. I come from an Emacs/Slime/Lisp(SBCL) on Windows, not Linux, and now that MS has open sourced a lot of it, I am going to stick with it and see if I hit any blocks. Popularity or cool are not my guides. I do have Linux and Mac OS X at home too, but I am always on my Windows notebook.