I'm a fan of EditPlus. It isn't wysiwyg... but when you're coding PHP, you don't really want wysiwyg. Has syntax highlighting, auto-complete, a great cliptext feature where you can store frequently used chunks of code (comes with a ton already configured), a cool directory browser that is unobtrusive to the code window, and finally a built in ftp client. Also, it unlimited in the type of code it can handle, because it supports custom syntax and auto-complete files. If you code in a bunch of different languages, you can do it all with EditPlus.
I use it for everything I do... PHP, C/C++, HTML, etc.
No, I don't work for the company that makes it. 😉 🙂