PHPEclipse is an Eclipse plugin that turns Eclipse into a PHP IDE.  I don't usually do PHP work, but a close friend of mine asked me to review his company's PHP-based website so I had to review a massive body of PHP code within only a few hours I could spare.

While any text editor can be used to write PHP code, mere text editors are not enough when you don't have much time to cover a lot of code.  So installed PHPEclipse and found it to be really nice.  It checks syntax and helps you trace and navigate call hierarchies easily.  I haven't tried its debugging capabilities, but I was delighted enough with just the capabilities I used to recommend it to PHP developers.

BTW, I am not a PHP developer and I don't build websites for small businesses.  It's not that that is not a respectable business.  It's just that I don't like doing what millions of others developers can with adequate competence.  Yes, I am a prima donna of sort.