IntelliJ 12 Darcula + Monokai
Loïc Descotte shared via Twitter an excellent color scheme for IntelliJ inspired by Monokai color scheme.

You can grab it at the following link (Monokai color scheme) or get the complete corresponding settings jar file here.
Setup is simple, under OS X you have to do the following (and then
select the corresponding color scheme in settings) :
cp ~/Downloads/GreaterMonokai.xml ~/Library/Preferences/IntelliJIdea12/colors/