Some Wordpress plugins are often updated, which is good think. Plugins that are updated are 100% compatible with last Wordpress version and they also are the most secure possible. A plugin that has not been updated for a long time might not work with last Wordpress version and might create a security breach for you website.
See http://www.andrewferguson.net/wordpress-plugins/dunstan-style-error-page/ for the latest updates.
Adds a sidebar widget for use with Andrew Sutherland's Democracy Poll widget.
WP Grins will provide clickable smilies for both the post form in the admin interface and the comments form of your blog.
This plugin will allow you to add an "Bookmark this page on del.icio.us/digg/furl/newsvine/blinklist" link on you sidebar / posts / wherever …
Instantly generates a guestbook for Wordpress blogs based on the active theme.
Spell checker for Wordpress using Ajax.
When selecting a child category in a post, this plugin automatically selects its parent categories
Allows you to change your post slugs without breaking your permalinks.
Set the location of the RSS and Atom feeds in options. Enables the use of services like FeedBurner without editing templates.
Inserts a quicktag toolbar on the blog comment form. js_quicktags is a slightly modified version of Alex King's newer Quicktag.js plugin modified from original found here.