As an IntelliJ IDEA user, you may notice user interface changes from version to version. And IMHO it looks better and better. Anyway, there are always some guys who don’t like any UI changes. To make these users feel comfortable with changes we made, I wrote a plugin that enables old IntelliJ icons.
Download the plugin from here http://bulenkov.com/idea11icons.jar Then go to IDEA Preferences -> Plugins -> Install from disk. Then restart IDEA.
UPDATE: The plugin has been updated to version 1.1 due compatibility issues with IntelliJ IDEA 13. Please download again and re-install