NetBeans IDE
The other day I had hit a brick wall, I was really struggling with part of my FormManager project and really needed to debug it.
I started looking into XDebug and discovered what it could really do, and diving into the website I found they listed a set of compatible IDEs that could use the extension to debug php. Since I had spurned eclipse I thought there was nothing else short of the Zend IDE that could help. Thats when I noticed NetBeans. The last time I had used NetBeans was back in college for some Java projects. I was really surprised when I found out that they offered a PHP IDE.
Within a couple of seconds of getting the project setup in the IDE it found the problem already for me. It does a much better job of context sensitive variables than Eclipse ever did, and it can pick up all kinds of problems much better than Eclipse, within a few minutes I had fixed the problem and even found a couple of problems that I did not yet know about.
It even includes some basic refactoring tools!
NetBeans does support Unit Testing however there is currently no support for phpUnit at this time. It is planned as a feature some point in the future.