If I could have an IntelliJ-level IDE for Ruby or Python or JS I'd be very happy.
The company behind IntelliJ already makes IDEs for Ruby, Python and JS:
Python: Pycharm http://www.jetbrains.com/pycharm/
Ruby: RubyMine http://www.jetbrains.com/ruby/
JS: Webstorm http://www.jetbrains.com/webstorm/