Index: includes/bootstrap.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/bootstrap.inc,v
retrieving revision 1.206
diff -u -r1.206 bootstrap.inc
--- includes/bootstrap.inc	10 Jan 2008 22:47:17 -0000	1.206
+++ includes/bootstrap.inc	9 Mar 2008 03:17:51 -0000
@@ -444,7 +444,7 @@
  * @return
  *   The value of the variable.
  */
-function variable_get($name, $default) {
+function variable_get($name, $default = NULL) {
   global $conf;
 
   return isset($conf[$name]) ? $conf[$name] : $default;
Index: includes/file.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/file.inc,v
retrieving revision 1.122
diff -u -r1.122 file.inc
--- includes/file.inc	17 Feb 2008 20:01:49 -0000	1.122
+++ includes/file.inc	9 Mar 2008 03:22:52 -0000
@@ -918,7 +918,7 @@
  * @return A string containing a temp directory.
  */
 function file_directory_temp() {
-  $temporary_directory = variable_get('file_directory_temp', NULL);
+  $temporary_directory = variable_get('file_directory_temp');
 
   if (is_null($temporary_directory)) {
     $directories = array();
Index: modules/color/color.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/color/color.module,v
retrieving revision 1.39
diff -u -r1.39 color.module
--- modules/color/color.module	23 Jan 2008 09:43:25 -0000	1.39
+++ modules/color/color.module	9 Mar 2008 03:22:52 -0000
@@ -54,7 +54,7 @@
   if ($form_id == 'system_theme_select_form' || $form_id == 'system_themes') {
     $themes = list_themes();
     foreach (element_children($form) as $theme) {
-      if ($screenshot = variable_get('color_'. $theme .'_screenshot', NULL)) {
+      if ($screenshot = variable_get('color_'. $theme .'_screenshot')) {
         if (isset($form[$theme]['screenshot'])) {
           $form[$theme]['screenshot']['#value'] = theme('image', $screenshot, '', '', array('class' => 'screenshot'), FALSE);
         }
@@ -110,7 +110,7 @@
   }
 
   // Override logo.
-  $logo = variable_get('color_'. $theme_key .'_logo', NULL);
+  $logo = variable_get('color_'. $theme_key .'_logo');
   if ($logo && $vars['logo'] && preg_match('!'. $theme_key .'/logo.png$!', $vars['logo'])) {
     $vars['logo'] = base_path() . $logo;
   }
Index: modules/locale/locale.install
===================================================================
RCS file: /cvs/drupal/drupal/modules/locale/locale.install,v
retrieving revision 1.28
diff -u -r1.28 locale.install
--- modules/locale/locale.install	6 Feb 2008 19:38:27 -0000	1.28
+++ modules/locale/locale.install	9 Mar 2008 03:22:52 -0000
@@ -172,7 +172,7 @@
 function locale_update_6005() {
   foreach (node_get_types() as $type => $content_type) {
     // Default to NULL, so we can skip dealing with non-existent settings.
-    $setting = variable_get('language_'. $type, NULL);
+    $setting = variable_get('language_'. $type);
     if ($type == 'default' && is_numeric($setting)) {
       // language_default was overwritten with the content type setting,
       // so reset the default language and save the content type setting.
Index: modules/profile/profile.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/profile/profile.module,v
retrieving revision 1.236
diff -u -r1.236 profile.module
--- modules/profile/profile.module	3 Feb 2008 19:36:46 -0000	1.236
+++ modules/profile/profile.module	9 Mar 2008 03:22:52 -0000
@@ -148,7 +148,7 @@
     $fields['user_profile'] = t('Link to full user profile');
     $form['profile_block_author_fields'] = array('#type' => 'checkboxes',
       '#title' => t('Profile fields to display'),
-      '#default_value' => variable_get('profile_block_author_fields', NULL),
+      '#default_value' => variable_get('profile_block_author_fields'),
       '#options' => $fields,
       '#description' => t('Select which profile fields you wish to display in the block. Only fields designated as public in the <a href="@profile-admin">profile field configuration</a> are available.', array('@profile-admin' => url('admin/user/profile'))),
     );
Index: modules/system/system.install
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.install,v
retrieving revision 1.240
diff -u -r1.240 system.install
--- modules/system/system.install	23 Feb 2008 08:13:09 -0000	1.240
+++ modules/system/system.install	9 Mar 2008 03:22:52 -0000
@@ -134,7 +134,7 @@
 
     // Determine when cron last ran. If never, use the install time to
     // determine the warning or error status.
-    $cron_last = variable_get('cron_last', NULL);
+    $cron_last = variable_get('cron_last');
     $never_run = FALSE;
     if (!is_numeric($cron_last)) {
       $never_run = TRUE;
@@ -2315,7 +2315,7 @@
  */
 function system_update_6042() {
   foreach (list_themes() as $theme) {
-    $stylesheet = variable_get('color_'. $theme->name .'_stylesheet', NULL);
+    $stylesheet = variable_get('color_'. $theme->name .'_stylesheet');
     if (!empty($stylesheet)) {
       variable_set('color_'. $theme->name .'_stylesheets', array($stylesheet));
       variable_del('color_'. $theme->name .'_stylesheet');
Index: modules/user/user.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/user/user.module,v
retrieving revision 1.896
diff -u -r1.896 user.module
--- modules/user/user.module	20 Feb 2008 13:46:43 -0000	1.896
+++ modules/user/user.module	9 Mar 2008 03:22:52 -0000
@@ -2363,7 +2363,7 @@
     // and never touch it on user edit pages.
     $form['timezone'] = array(
       '#type' => 'hidden',
-      '#default_value' => variable_get('date_default_timezone', NULL),
+      '#default_value' => variable_get('date_default_timezone'),
       '#id' => 'edit-user-register-timezone',
     );