I like.

It's not obvious in the diff, but does this allow setting the value 'once' like so:

$this->Html->pathPrefix = '//cakephp.org/css';
$this->Html->css('foo'); // http://cakephp.org/css/foo.css
$this->Html->css(array('bar', 'spam'); // http://cakephp.org/css/bar.css http://cakephp.org/css/spam.css