On of the editors I use a lot is Eclipse PDT. First of all I like it, of course, but also because it’s cross platform and I got it working great in both Linux, Mac and Windows. I love it when I do object oriented PHP-work. The code completion sence the classes I’ve created and gives me a list of my own methods when I type. This is of course avilable in other editors also, but the whole package in Eclipse PDT and versitility makes it my favorite editor.

Code completion in Eclipse PDT