WordPress Must-Have plugins

In as much as I have a no plugin law here, I do believe there are exceptions to the rule based on the kind of site you run.

All sites

1. Akismet Spam protection. It comes pre-bundled with your WordPress installation
2. WordPress SEO by Yoast For Search-Engine Optimization (SEO)

Blog

1. Disqus For comments
2. Autochimp To send out emails to everyone subscribed to your blog whenever you post new content

This list is updated from time-to-time whenever a new gem is discovered. If you do have a plugin you feel ought to feature here, do share