Update – 19th July, 2012.
This article and the one linked to below are pretty dated now, so you may want to take a look at my most recent article on plugins:
Core plugins for any WordPress site.
Original article starts here:
A while ago I put up a list of recommended WordPress plugins, that I use on new blogs. They’re broken down by various categories: SEO related, security related and so on.
Since then I’ve found and used some others, and my Twitter friend @michaeldcarney reminded me that I should update the original list.
So here are some more:
Broken Link Checker: Checks your entire blog for broken links in posts or pages and puts a message in your Dashboard when it finds some. Offers you various options for dealing with them – e.g. you can ignore the notice, remove the link, edit the link, etc.
Related Sites: Operates like related posts, but finds related articles on other blogs and places links to them at the bottom of your articles. Also places links to your articles on other blogs. Reviewed in more detail here.
Thesis Open Hook Note – this is only useful for users of the Thesis theme (but it is very useful for them!). Enables Thesis users to make easier use of the custom functions file without having to learn about hooks. Greatly empowers less technical Thesis users. Reviewed in more detail here.
Blog Copyright Places a copyright notice in your footer (all posts and pages) and automatically updates the year range as the year changes.
The original list of recommended plugins is here and I’ll be sure to add more to this series as I find and use them.
Update 7th May, 2009:
I’ve seen a lot of questions asking how to install new plugins on WordPress, so I’ve written a step-by-step process.
Also, some more recommended plugins – find them here.