IntelliJ IDEA (http://www.jetbrains.com/idea/) has good JavaScript support, including refactoring. I also quite like Komodo Edit (http://www.activestate.com/komodo-edit), since it's more lightweight but has JavaScript code completion & is easily extensible.

While you're looking at Node, I also suggest you take a look at RingoJS (http://ringojs.org/). It should be easier to get started with & has debugging support.