I wrote an article on my blog today about the top ten WordPress plugins I find useful. I thought some of you might enjoy it, because no matter how long you've used WordPress, you keep on finding new, cool plugins.
You can read the article here: http://cavemonkey50.com/2006/03/the-top-ten-wordpress-plugins/
Also, if you have any suggestions on other WordPress plugins to add to the list, feel free to comment away. I'm curious on what other people think of as the essentials.