I have just recently installed a whole new set of WordPress plugins to this blog:

Angsuman's Referrer Bouncer, Bad Behavior and http:BL WordPress Plugin are anti-comment spam tools. Angsuman's Referrer Bouncer automatically bounces referer spammers back to their own sites. Bad Behavior is a PHP-based solution for blocking link spam and the robots which deliver it. The http:BL WordPress Plugin checks IP addresses of clients connecting to your blog against the Project Honey Pot database. All 3 of these plugins prevent any potentially harmful clients from accessing your blog. Since installing these plugins I have had no spam comments at all.

AntiLeech is used to help prevent content theft by Sploggers. It prevents errant parties from stealing your content and bandwidth by producing a fake set of content especially for them that includes links back to your site. When they steal this content, it appears online just like normal, except now you've turned the tables on them and have provided them with useless content.

Diagnosis adds a debugging page to your WordPress Dashboard so that you can easily debug problems in your WordPress installation or plugins. It also tells you information about your server, MySQL database and PHP settings.

Dofollow is used for the "U Comment, I Follow Movement". The plugin removes the "dead end" piece of code inserted wherever there is a link in a comment, so that search engines will now follow the links as they are crawling the internet. The name was given to this movement by Randa Clay Design and people are now starting to add logos/images to there website stating that they are part of the movement. I joined in and created my own button-image on my blog's footer, to remove the "nofollow" code on comments I had to install this plugin.

Google (XML) Sitemaps automatically creates a sitemap for your blog that search engines can use to quickly, simply and easily index pages from your website. Ultimate Google Analytics automatically installs the Google Analytics code so that you do not need to do it manually. WordPress.com Stats allows you to track your blogs statistics as if your blog was created at WordPress.com.

I would advise that you download and install these plugins to your own WordPress-powered blog as they are extremely helpful. Also, take a look at this blogs complete list of used plugins.