I want it to be Scala so much as well, I don't want to start learning Go. (Although I heard great things about it, just after learning Scala, I don't want to learn a new language for a few years now)
Outside of the JVM, and for consumer apps, I am starting to think node.js is going to be the winner. It's not there yet. However, as more and more pages go to client-side apps and significant mobile presences, node is building a good enough ecosystem. Working in a single language is nice, though I think the callback system is clumsy. (That's what async or q is for. though I prefer Scala's actor model)
It wasn't right for us on this project, but I can definitely see going back to it for other projects.
I think writing one language both server and client is a big yes for node.js, but looking at my client-side code vs my server code (and I'm writing Javascript since 2001, way before I learned Java) I come to the understanding why Google are investing so much in Dart / GWT (which I think are not there yet)
If Scala/Haskell/Go would become more mainstream, and had a very straight forward / magic-free 1:1 conversion to javascript, then node.js will have much less appeal to me.
