Release candidate 1 for Scala 2.9 is out. It has some interesting new features, such as parallel collections: when you call for example foreach on these, the iteration will be done in parallel when you have a multi-core processor. And there are lots of other interesting new features.
I've tried the parallel collections out a little bit, this makes it really incredibly easy to write multi-threaded code. (Ofcourse you still have to be careful with mutable data, synchronization etc. but you don't have to write any low-level plumbing code with threads or actors anymore). Wrote a short blog post about it.