diff -u modules/system/admin.css modules/system/admin.css
--- modules/system/admin.css	2008-01-20 14:33:06.000000000 +0000
+++ modules/system/admin.css	2008-01-20 14:23:47.000000000 +0000
@@ -82,6 +82,14 @@
 table.system-status-report tr.ok th {
   background-image: url(../../misc/watchdog-ok.png);
 }
+tr .number {
+  text-align: right;
+  padding-right: 2em;
+}
+td.warning {
+  background-color: yellow;
+  color: red;
+}
 /**
  * Formatting for theme configuration
  */
diff -u modules/system/system.admin.inc modules/system/system.admin.inc
--- modules/system/system.admin.inc	2008-01-20 14:49:06.000000000 +0000
+++ modules/system/system.admin.inc	2008-01-20 14:41:31.000000000 +0000
@@ -1756,14 +1756,17 @@
  *   The output HTML.
  */
 function _system_sql($data, $keys) {
+  static $zero_keys = array('Select_full_join', 'Sort_scan', 'Qcache_lowmem_prunes');
+  
   $rows = array();
   foreach ($keys as $key => $explanation) {
     if (isset($data[$key])) {
-      $rows[] = array(check_plain($key), check_plain($data[$key]), $explanation);
+      $not_zero = ($data[$key] != 0 && in_array($key, $zero_keys));
+      $rows[] = array(check_plain($key), array('data' => check_plain($data[$key]), 'class' => 'number'. (($not_zero)? ' warning': '')), $explanation);
     }
   }
 
-  return theme('table', array(t('Variable'), t('Value'), t('Description')), $rows);
+  return theme('table', array(t('Variable'), array('data' => t('Value'), 'class' => 'number'), t('Description')), $rows);
 }
 
 /**