I have been working with the Eclipse PDT editor for quite a while now and it impressed me so much that it became my primary editor.
I have worked with Dreamweaver, Zend Studio (this is another extreme great product), Notepad, Edit+ (you should have it – is a life savier) and so many others, but the Eclipse PDT provided me enough tools to work with Zend Framework, core PHP related development, JS scripts, CSS and XML (which is pretty good).
There is a big drawback dough. If you are using Linux (Xubuntu in my case) you should download the Eclipse PDT from their site and not using any installer, since the versions that they have will break with current java versions.
Besides that, is a great FREE PHP editor.
I always try to help any organization that is development related and will be doing some conference or some event, so…