For what it's worth I couldn't disagree more. I use the guard pattern very often (as described here http://video.ias.edu/webfm_send/1207 [Video]).

Rather than writing:

   if (argc == 3) {
      if (fname) {
         /* Do stuff */
      } else {
         printf ("File name cannot be null");
      }
   } else {
      printf ("Wrong number of arguments");
   }

I would write:

   if (argc != 3) {
      printf ("Wrong number of arguments");
   } else if (!fname) {
      printf ("File name cannot be null");  
   } else {
      /* Do stuff */
   }