Index: wp-includes/ms-functions.php
===================================================================
--- wp-includes/ms-functions.php	(revision 19126)
+++ wp-includes/ms-functions.php	(working copy)
@@ -991,8 +991,12 @@
 	add_option( 'WPLANG', get_site_option( 'WPLANG' ) );
 	update_option( 'blog_public', (int)$meta['public'] );
 
-	if ( !is_super_admin() && ! get_user_meta( $user_id, 'primary_blog', true ) )
-		update_user_meta( $user_id, 'primary_blog', $blog_id );
+	if ( ! is_super_admin( $user_id ) ) {
+		if ( ! get_user_meta( $user_id, 'primary_blog', true ) )
+			update_user_meta( $user_id, 'primary_blog', $blog_id );
+		if ( ! metadata_exists( 'user', $user_id, 'show_welcome_panel' ) )
+			update_user_meta( $user_id, 'show_welcome_panel', 1 );
+	}
 
 	restore_current_blog();
 	do_action( 'wpmu_new_blog', $blog_id, $user_id, $domain, $path, $site_id, $meta );
Index: wp-admin/admin-ajax.php
===================================================================
--- wp-admin/admin-ajax.php	(revision 19126)
+++ wp-admin/admin-ajax.php	(working copy)
@@ -1067,10 +1067,7 @@
 	if ( ! current_user_can( 'edit_theme_options' ) )
 		die('-1');
 
-	if ( empty( $_POST['visible'] ) )
-		delete_user_option( get_current_user_id(), 'show_welcome_panel' );
-	else
-		update_user_option( get_current_user_id(), 'show_welcome_panel', 1 );
+	update_user_meta( get_current_user_id(), 'show_welcome_panel', empty( $_POST['visible'] ) ? 0 : 1 );
 
 	die('1');
 	break;
Index: wp-admin/includes/upgrade.php
===================================================================
--- wp-admin/includes/upgrade.php	(revision 19126)
+++ wp-admin/includes/upgrade.php	(working copy)
@@ -77,6 +77,9 @@
 		$message =  __('User already exists. Password inherited.');
 	}
 
+	if ( $user_id )
+		update_user_meta( $user_id, 'show_welcome_panel', 1 );
+
 	$user = new WP_User($user_id);
 	$user->set_role('administrator');