I'm well into learning Scala now and enjoying it very much; I hope to start future projects in it, rather than Java. What I'm enjoying less is the (relatively) poor IDE support. I've found both IDEA and Eclipse with the Scala Plugin (including nightly builds) to be a bit unreliable or difficult to use - I want something I can always depend on. E.g. yesterday I couldn't get a fresh install of eclipse+plugin to run my tests at all, or even open an editor window!
I'm considering hopping between Eclipse/IDEA depending on which suits the task at hand best and more importantly cutting my dependence on the IDE for building and running tests (ScalaTest). This is non-trivial for me since I've grown up on Java in Eclipse; leaving Eclipse SVN to use GIT was initially a big deal. Given that I only have time to learn one tool, should it be Ant, Maven, buildr, sbt,.... ? How do other people work?