Index: commands/pm/pm.drush.inc
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/drush/commands/pm/pm.drush.inc,v
retrieving revision 1.121
diff -u -p -r1.121 pm.drush.inc
--- commands/pm/pm.drush.inc	18 Aug 2010 05:38:42 -0000	1.121
+++ commands/pm/pm.drush.inc	23 Aug 2010 17:33:28 -0000
@@ -980,7 +980,12 @@ function pm_dl_destination_lookup($type,
       }
       break;
     case 'theme':
+      // Prefer sites/all/themes/contrib if it exists.
       $destination = $sitepath . 'themes/';
+      $contrib = $destination . 'contrib/';
+      if (is_dir($contrib)) {
+        $destination = $contrib;
+      }
       break;
     case 'theme engine':
       $destination = $sitepath . 'themes/engines/';