There comes a time where it's unacceptable or inconvenient to stash var_dump() into your code. And then there's Xdebug. Xdebug makes it easy to debug your PHP application and with the intergration of NetBeans, it's even easier.
For the record, I'm using Debian 6.0.4 on my workstation and Debian Wheezy/Sid on my dev server.
First of all, lets install Xdebug on the server:
pecl install xdebug
Open up your xdebug.ini file, mine is located at /etc/php5/cgi/conf.d/xdebug.ini, and enable Xdebug. My xdebug.ini looks like this:
zend_extension=/usr/lib/php5/20100525+lfs/xdebug.so
xdebug.remote_enable=1
xdebug.remote_connect_back=1
xdebug.remote_handler=dbgp
xdebug.remote_mode=req
xdebug.remote_port=9000
xdebug.idekey=netbeans-xdebug