gistfile1.el

(defun intelligent-close ()
  "quit a frame the same way no matter what kind of frame you are on"
  (interactive)
  (if (eq (car (visible-frame-list)) (selected-frame))
      ;;for parent/master frame...
      (if (> (length (visible-frame-list)) 1)
          ;;close a parent with children present
          (delete-frame (selected-frame))
        ;;close a parent with no children present
        (when (y-or-n-p "Quit emacs? ") (save-buffers-kill-emacs)))
    ;;close a child frame
    (delete-frame (selected-frame))))
(global-set-key (kbd "C-x C-c") 'intelligent-close)