Respectable people (1, 2) are still looking at the Scala programming language for the JVM. I took a reasonably deep dive on it back in the summer. As I wrote back then, I've tinkered back in the day with SML, Haskell (and a bit of other functional languages like Clean). But being significantly deeper into "dynamic" languages like Lisp, Smalltalk, and now somewhat Python and Ruby, I never really got over the curve of "thinking in types".
There is a difference between "type-driven programming" and "test-driven" (or in Lisp, repl-driven, or in Smalltalk, workspace-driven). I'm not sure what "type-driven" feels like in real settings. And so after a week of kicking Scala's tires off and on, I decided it's nice but not enough in my wheelhouse to get excited about.
Reading folks blogging about their own Scaladventures and reading that a new book (400+ pages!! That could be good or bad) is available (currently as a draft), I purchased the book and will tinker again, at least for a few more days, with Scala.
I just got my access key to Amazon's Simple DB, so maybe I'll dream up something interesting there with Scala. Integrating the dynamic, semi-structured nature of systems like Simple DB with the compile-time rich type checking of a language like Scala is an ongoing area of, em, interest. Dynamic languages never get in my way with things like Simple DB.