The following is a list Free and Paid WordPress plugins that Declan recommended for use on your WordPress website. They are part of a session he gave at WordPress Ann Arbor. If you have any other suggestions you think should be added to the list, please feel free to leave your recommendations in the comments below.
Contact Forms for WordPress Just Don’t Get Any Easier than Gravity Forms. Quickly build and design your WordPress forms using the form editor. Select your fields, configure your options, and easily embed forms on your WordPress powered site using the built in tools. Gravity Forms requires a minimum of WordPress version 3.0, MySQL 5 and PHP 5 in order to function properly. Please note that Gravity Forms is not compatible with the WordPress.com hosted service. Gravity Forms costs $39.99 for a personal license.
WP-DB-Backup allows you easily to backup your core WordPress database tables. You may also backup other tables in the same database.
Redirection is a WordPress plugin to manage 301 redirections, keep track of 404 errors, and generally tidy up any loose ends your site may have. This is particularly useful if you are migrating pages from an old website, or are changing the directory of your WordPress installation.
Broken Link Checker
This plugin will check your posts, comments and other content for broken links and missing images, and notify you if any are found.
Search and Replace
A simple search for find strings in your database and replace the string. You can search in ID, post-content, GUID, titel, excerpt, meta-data, comments, comment-author, comment-e-mail, comment-url, tags/categories and categories-description. It is possible to replace the user-ID in all tables and the user-login for more security in the WordPress-Application
This plugin gives every widget an extra control field called “Widget logic” that lets you control the pages that the widget will appear on.
The Cart66 WordPress ecommerce plugin makes it easier to make money online than ever before. Not only can you sell physical products, digital products, and services, Cart66 will also turn your WordPress site into a membership website allowing you to sell subscription access to your content.
Theme My Login
This plugin themes the WordPress login, registration and forgot password pages according to your current theme. It replaces the wp-login.php file by using a page template from your theme. Also includes a widget for sidebar login.
WordPress SEO Plugin
WordPress SEO is the most complete WordPress SEO plugin that exists today for WordPress.org users. It incorporates everything from a snippet preview and page analysis functionality that helps you optimize your pages content, images titles, meta descriptions and more to XML sitemaps, and loads of optimization options in between.
Woopra Analytics for WordPress
This plugin adds Woopra’s real-time analytics to any WordPress installation
Akismet filters out your comment and track-back spam for you, so you can focus on more important things.