Here is the top list of plugins for WordPress that I believe were a must have of 2008. In no particular order:

  1. Redirection

    Redirection is an easy way to create 301 redirections and keep track of 404 errors, it makes it extremely easy to create 301 redirections to posts/pages and outside links, it will automatically add a redirection to a post/page when it's permalink changes, so that you do not loose visitors to a 404 error page. Keeping track of all of the 404 errors your blog spits out is also extremely useful, because it means you can fix broken links and stop visitors from landing on the wrong page.

  2. Exec-PHP

    This plugin allows execution of PHP code in your posts, pages and text widgets. It executes PHP code in the excerpt and the content portion of your posts and pages and restricts execution of PHP code in posts and pages to certain users by using roles and capabilities.

  3. Contact Form 7

    Contact Form 7 is a simple, lightweight and flexible contact form. It allows you to create a large amount of contact forms and easily embed them into any post/page. It is very easy to configure and does not have an options page stuffed full with Ajax. I chose this plugin in place of cforms II because it is lightweight. The cforms II plugin has too much junk, for such a small thing. If cforms II wasn't so slow, it would surely take this plugins place.

  4. WP-DB-Backup

    WordPress database backup creates backups of your core WordPress tables as well as other tables of your choice in the same database. You can schedule it to backup your database hourly, twice daily, once daily or weekly. I have it scheduled once daily so that if anything goes kaput I don't have to start from square one. However, it does lack some useful features such as download links, listing, restore, deleting and specific schedule time). I have updated it myself to include some of these features and may release it later on.

  5. Subscribe To Comments

    Subscribe to Comments allows commenters on your blog to check a box before commenting and get e-mail notification of further comments. It is one of the most popular WordPress plugins out there for the simple reason that it helps foster a community around your blog by encouraging commenters to come back and stay engaged in the dialog.

  6. Lifestream

    Lifestream displays your social feeds and photos much like you would see it on many of the social networking sites. It is a good way to let your readers know what and where you are on the web. It can be setup for an unlimited number of feeds, and stores the entire feed history. Best of all it's efficient; it's built on scalable database structures so it won't bog down your website.

  7. Ajax Edit Comments

    Ajax Edit Comments allows users and admins to edit comments on a post. Users can edit their own comments for a limited time, while admins can edit all comments on the fly. It attaches a few links to the bottom of comments to allow admins to edit, de-link, delete and mark as spam without ever having to access the WordPress dashboard.

  8. Twitter Tools

    For all you Twitter freaks out there! Twitter Tools is a plugin that creates a complete integration between your WordPress blog and your Twitter account. It enables you to archive your tweets, tweet from your WordPress dashboard, create digest blog posts from your tweets and tweet about recent posts automatically.

  9. ©Feed

    This plugin extends your default feed and allows you to add information such as copyright, a digital fingerprint and the IP of the feed reader to eliminate content theft. The feed can be also be supplemented with comments and topic-relevant contributions.

  10. WP-PostViews

    WP-PostViews counts the number of hits each post receives and allows you to display the most popular posts. This plugin is veru helpful for gathering valuable statistics for certain types of posts, so that you know what to write more or less of in the future.