If you are looking to do PHP development in Eclipse, TruStudio from xored software is a very good candidate as an IDE/plugin.
I used it in the past when it was fully open-source and liked it. I have not had a chance to try it again since then, although their marketing e-mail sounds promising. The products page, when I finally looked at it, lists two versions of the plugin: foundation and professional. The features page further lists in details all the capabilities of TruStudio together with markings to differentiate the free foundation version from the professional one.
If I have to do further PHP coding, I will seriously consider this, despite my reservations towards Eclipse.