I had to change to a new PC so it was a good chance to re-install applications and start from fresh. Along the way I discovered a cool Firefox extension that works with FireBug for helping with debugging PHP.
For those people that don't know, Firebug is a Firefox extension that allows you to examine the HTML and CSS of web pages and more. But FireLogger adds another panel to FireBug to log messages sent from your PHP script for debugging purposes.
FireLogger uses HTTP so as not to interfere with the appearance of the web page. This also means that you can debug Ajax applications. There is example code given for this in the download. A PHP include file is needed to be added to your web page to enable the functionality.
I see this as being very useful for debugging obscure WordPress bugs with plugins where sometimes, there is nothing to see in the web browser.
FireLogger server logger console in Firebug