Sitepoint did a survey recently to find out the best PHP IDE from it’s readers. The results of over 4000 participants were overwhelmingly in favor of PHPStorm.
PhpStorm is an offspring of IntelliJ IDEA, the Jetbrains Java IDE, and is basically a stripped down version with PHP support embedded. Due to this plugin based nature,
PhpStorm can support other languages just as easily, allowing you to develop NodeJS, Dart, Go and other language apps in the same environment.