Index: wp-includes/default-filters.php
===================================================================
--- wp-includes/default-filters.php	(revision 18656)
+++ wp-includes/default-filters.php	(working copy)
@@ -182,7 +182,7 @@
 add_filter( 'option_siteurl',           '_config_wp_siteurl'                  );
 add_filter( 'tiny_mce_before_init',     '_mce_set_direction'                  );
 add_filter( 'pre_kses',                 'wp_pre_kses_less_than'               );
-add_filter( 'sanitize_title',           'sanitize_title_with_dashes'          );
+add_filter( 'sanitize_title',           'sanitize_title_with_dashes',   10, 3 );
 add_action( 'check_comment_flood',      'check_comment_flood_db',       10, 3 );
 add_filter( 'comment_flood_filter',     'wp_throttle_comment_flood',    10, 3 );
 add_filter( 'pre_comment_content',      'wp_rel_nofollow',              15    );
Index: wp-includes/formatting.php
===================================================================
--- wp-includes/formatting.php	(revision 18656)
+++ wp-includes/formatting.php	(working copy)
@@ -803,7 +803,7 @@
 }
 
 /**
- * Sanitizes title, replacing whitespace with dashes.
+ * Sanitizes title, replacing whitespace and a few other characters with dashes.
  *
  * Limits the output to alphanumeric characters, underscore (_) and dash (-).
  * Whitespace becomes a dash.
@@ -811,9 +811,11 @@
  * @since 1.2.0
  *
  * @param string $title The title to be sanitized.
+ * @param string $raw_title Optional. Not used.
+ * @param string $context Optional. The operation for which the string is sanitized.
  * @return string The sanitized title.
  */
-function sanitize_title_with_dashes($title) {
+function sanitize_title_with_dashes($title, $raw_title = '', $context = 'display') {
 	$title = strip_tags($title);
 	// Preserve escaped octets.
 	$title = preg_replace('|%([a-fA-F0-9][a-fA-F0-9])|', '---$1---', $title);
@@ -832,6 +834,16 @@
 	$title = strtolower($title);
 	$title = preg_replace('/&.+?;/', '', $title); // kill entities
 	$title = str_replace('.', '-', $title);
+
+	if ( 'save' == $context ) {
+		// ndash and mdash
+		$title = str_replace( array( '%e2%80%93', '%e2%80%94' ), '-', $title );
+		// curly quotes and hellip
+		$title = str_replace( array( '%e2%80%9c', '%e2%80%9d', '%e2%80%98', '%e2%80%99', '%e2%80%a6' ), '', $title );
+		// copy and trade
+		$title = str_replace( array( '%e2%84%a2', '%c2%a9' ), '', $title );
+	}
+
 	$title = preg_replace('/[^%a-z0-9 _-]/', '', $title);
 	$title = preg_replace('/\s+/', '-', $title);
 	$title = preg_replace('|-+|', '-', $title);