- PHPStorm
Many said this is the best, but cost $99 for individual purchase. - NetBeans 7
I just started to use it. My verdict is 10 out of 10 at least for now. The big difference between Netbeans and Eclipse PDT is that you can do pretty much all you need to use just out of the box, which includes Xdebug, SVN. On top of these, NetBeans is more table and convenient to use. Configuration is not complex as Eclipse. It’s rather simple like Mac interface. So cool so far. I love it. and it’s freeware. - Eclipse PDT (+ Aptana as plug-in)
This is quite popular IDE and I used it for my subject for java enterprise development. That’s why I started using it when I first start developing PHP. But, it was horrible mistake. Eclipse PDT is bumpy, unexpected shutdown, buggy, compatibility issues almost whenever it’s updated. Have to install SVN, X-Debug plug-in manually and those are complicated work like hell. You must spend more than for setup than coding.