.htaccess Site Access Control plugin allows you to password protect your site: WP login page, admin pages, and/or the whole site.
Remove Feed Links is a simple plugin for removing feed links from the head of your web site.
Allows you to have one landing page, with different versions depending on the keyword -- so you can show each visitor a customized version of it!
The Square Bracket Hack Prevention plugin prevents hackers from adding a "[" to the URL.
The Keyword Counter & Density Calculator plugin calculates how many times and how commonly each keyword is used in a post or a page.
Site Language Definition is a simple plugin for forcing the web browser to know what language your site is in.