Index: wp-includes/admin-bar.php
===================================================================
--- wp-includes/admin-bar.php	(revision 17094)
+++ wp-includes/admin-bar.php	(working copy)
@@ -126,7 +126,8 @@
 			$wp_admin_bar->add_menu( array( 'parent' => 'blog-' . $blog->userblog_id, 'id' => 'blog-' . $blog->userblog_id . '-c', 'title' => __( 'Manage Comments' ), 'href' => get_admin_url($blog->userblog_id, 'edit-comments.php') ) );
 		}
 
-		$wp_admin_bar->add_menu( array( 'parent' => 'blog-' . $blog->userblog_id, 'id' => 'blog-' . $blog->userblog_id . '-v', 'title' => __( 'Visit Site' ), 'href' => get_home_url($blog->userblog_id) ) );
+		if ( get_home_url($blog->userblog_id) != get_home_url() )
+			$wp_admin_bar->add_menu( array( 'parent' => 'blog-' . $blog->userblog_id, 'id' => 'blog-' . $blog->userblog_id . '-v', 'title' => __( 'Visit Site' ), 'href' => get_home_url($blog->userblog_id) ) );
 	}
 }