I have been using WordPress as the primary blog and mini-cms system for years. There are more than 8000 plugins for the system which sometimes makes it hard to find the right plugin. That is why I collected a list of the best plugins that I know (please make a comment if I missed an important plugin):
Must-have-plugins
Akismet
Akismet checks your comments against the Akismet web service to see if they look like spam or not.
Cookies for Comments
Sets a cookie that must exist for a comment to be allowed through. Prevents a lot of spam-bot of doing their business.
FeedBurner FeedSmith
This plugin detects all ways to access your original WordPress feeds and redirects them to your FeedBurner feed so you can track every possible subscriber.
kStats Reloaded
kStats Reloaded is one of the fastest real-time statistics plugins for WordPress. See who’s on your site, where they came from, and where they’re going.
Exclude Pages from Navigation
Provides a checkbox on the editing page which you can check to exclude pages from the primary navigation.
Used-most-of-the-time-plugins
All in One SEO Pack
Out-of-the-box SEO for your WordPress blog.
Ultimate Google Analytics
Enable Google Analytics on your blog. Has options to also track external links, mailto links and links to downloads on your own site.
Simple Tags
Extended Tagging for WordPress. Suggested Tags, Mass edit tags, Autocompletion, Tag Cloud Widgets, Related Posts, Related Tags, etc!
qTranslate
Adds userfriendly multilingual content support into WordPress.
WP Super Cache
Very fast caching plugin for WordPress. Needed if your site gets a lot of hits.
Nice-to-have-plugins
SexyBookmarks
SexyBookmarks adds a (X)HTML compliant list of social bookmarking icons to each of your posts.
Hacking-plugins
PHP Execution
The PHP Execution Plugin allows users to write php code inside their posts and pages. Embedded php code will be executed when the post is shown. In doing so, the plugin offers the possibility to utilize dynamic content inside of posts.
WP Tuner
Easily, powerfully, discover why your blog or plugin is slow or cranky. It’s a comprehensive time and database access analyzer.
Porcupine X is run by 
Hi Thier !
I love word press for their time saver features.Word press is good in many ways.
But Still their are many issues that makes word press a uncomfortable choice:
1. The pace between the plug-in development and word press development is quite different.
Means their are a very few plug-in left if you try to update your servers with all the latest enhancement from the word press.
2. Some Plug-in developers are quite slow specially when you need X plug-in and you see from last 3 months the developer is not interested in providing it. (It had happened to me).
So after all you need to develop it yourself.
(But Off course their are some vary perfect working examples of innovation And I respect their work too.)
3. The Plug-ins that have a commercial sense are rare. (Let me know if you found any interesting one)
I love to find more articles. Don’t bother I will check this place often.
–
Regards
Alok Tiwari
India
P.S. The article is more technical or Time Savers functionality. But I love to here to find the ways of revenue generation.. Any Idea clicks ?