Resolving dependencies can be quite time consuming because it requires contacting external repositories via your internet connection.
Even so, 30 minutes seems excessive. Maybe there's a network connectivity issue and something is hung indefinitely.
Or maybe there's something about your build script that causes excessive NW checking (lots of snapshot style depenencies comes to mind).
I'm not sure what advice to give you here. Maybe you can try running a gradle build from the commandline and see if that has similar behavior of getting totally 'hung'. I am guessing that probably it will. In that case I'd say the folks on the Gradle Forum (*) are probably the best ones to advise as the problem isn't specific to the tooling. They will be better able to help figure out what inside of your build script or Gradle itself is getting stalled.
Kris
(*) http://forums.gradle.org/gradle
Kris De Volder -- SpringSource