XDebug or Zend Debugger?
PhpDebuggingPhp Problem Overview
It seems to me that they have both the same function set, but I'm not sure.
What are the differences in functionality between the two?
Php Solutions
Solution 1 - Php
Zend debugger is only available in binary format, so you need to be careful to download the right version to match your version of php ( http://downloads.zend.com/pdt/server-debugger/ ). I was able to get it working with Eclipse PDT and do line-by-line debugging with a local XAMPP installation. I think Zend has some additional features, but in my experience it has been easier to set up.
XDebug is much more open, but I haven't successfully configured it to work with Eclipse PDT.
Solution 2 - Php
XDebug works with Eclipse and with Netbeans (and some other ide's).
ZendDebug doesn't work with Netbeans. ZendDebug is already configured in ZendServer.