My new favorite PHP IDE is Netbeans 6.9 . Netbeans is great for what I do, but your mileage may vary. First of all it uses a loss less ram then Eclipse which is great because I don’t have a lot. At work I have to use a very old Windows XP desktop, with only 1.5 gigs of ram so anytime I use Eclipse it really slows down the machine.
Netbeans has great Zend Framework integration and making it extremely easy to use Zend Tool. The only feature it lacks for me is jQuery integration. A nice add-on I found is called Path Tools, it makes it easy to copy a project path, open a window with the project directory selected or open a terminal window in the project. The requirements do not state 6.9 compatibility but I have not had any problems. BTW, there is a version of Path Tools for Eclipse.