I used to use dreamweaver for php coding. But now I have stopped using DW for php. I use maguma open studio.
Free yet the most advanced. It offers exactly what I need. Intellisense for both native and user functions. Cool class wizard for not only creating and manage classes, but also for understanding new codes. It even supports phpdoc comment syntax which simplifies writing documentation.
It does have some minus points. It's still buggy while closing the program sometimes. Otherwize perfect.