Most people would say start with SICP (http://mitpress.mit.edu/sicp/ http://mitpress.mit.edu/sicp/), and I think I would agree. It really stresses higher order

Most people would say start with SICP (http://mitpress.mit.edu/sicp/ http://mitpress.mit.edu/sicp/), and I think I would agree. It really stresses higher order programming. OCaml would be nice too, for you, since F# is at least as powerful as it, and you could start using that in your C# environment.