I really fall in love in Codelobster PHP Edition.
It's great free Portable PHP IDE.
It have all possibilities like requiring payment IDE, but it really smaller and faster.
It have pleasant interface and plugins for all most popular frameworks.
Especially i like HTML/CSS code inspector which shows all styles belonging to
selected element which can be edited at once in proper CSS file.
Also very important advantage of this product - plugins for
Drupal, Joomla, JQuery, Smarty, WordPress, Facebook, CakePHP and CodeIgniter.