Index: wp-includes/functions.php
===================================================================
--- wp-includes/functions.php	(revision 3657)
+++ wp-includes/functions.php	(working copy)
@@ -365,8 +365,7 @@
 		return true;
 	}
 
-	if ( is_array($newvalue) || is_object($newvalue) )
-		$newvalue = serialize($newvalue);
+	$newvalue = serialize($newvalue);
 
 	wp_cache_set($option_name, $newvalue, 'options');
 
@@ -395,8 +394,7 @@
 	if ( false !== get_option($name) )
 		return;
 
-	if ( is_array($value) || is_object($value) )
-		$value = serialize($value);
+	$value = serialize($value);
 
 	wp_cache_set($name, $value, 'options');