Add a class or ID per item?

It would be great if we could have a unique ID or class for each list item. I originally thought this could be done with the following PHP, however these are list items and not "menu" list items.

function phptemplate_menu_item_link($link) {
if (empty($link['localized_options'])) {
$link['localized_options'] = array();
}
if (empty($link['localized_options']['attributes']['class'])) {
$link['localized_options']['attributes']['class'] = 'menu-'. $link['mlid'];
}
else {
$link['localized_options']['attributes']['class'] .= ' menu-'. $link['mlid'];
}
return l($link['title'], $link['href'], $link['localized_options']);
}