All time I use:
print'<pre>';
print_r($var);
print'</pre>';
to debug php.
I want to collapse this tree
[params] => JRegistry Object
(
[data:protected] => stdClass Object
(
[show_title] =>
[link_titles] =>
[show_intro] =>
with jquery
Give Krumo a try - http://krumo.sourceforge.net/