I would like to prevent several contributed modules from using their own css files. Constantly having to reset their css and then apply your own is a waste of bandwidth IMO.
I tried this out with nice_menus and it didn't seem to do anything.
Placed in template.php
function phptemplate_variables($hook, $vars) {
$css = drupal_add_css();
$rm[] = drupal_get_path('module','nice_menus').'/nice_menus.css';
$rm[] = drupal_get_path('module','nice_menus').'/nice_menus_default.css';
foreach ($rm as $key => $value) {
unset($css['all']['module'][$value]);
}
$vars['styles'] = drupal_get_css($css);
}