In D7 what is the correct way to create a page template that has HEAD elements specific to that page?
Use hook_preprocess_html ( e.g in template.php ) to modify the html.tpl.php variables.

For different JS or CSS, check the path ( e.g current_path() == 'foo' ) and add with 


drupal_add_js or 
drupal_add_css 


Set the 'every_page' option, and perhaps preprocess flag to FALSE.