Wordpress is the best open source CMS (content management system). It became one of the most popular blogging and publishing platform on the web. You can get lots of articles about wordpress plugins over the internet. Plugins can extend WordPress to do almost anything you can imagine. Plugins can make your blog more interactive, sticky to keep visitors coming back for more and used by novices and power bloggers alike. There are near about 5,768 plugins on wordpress site for download. Following list is about just a few of the plugins I like and use. I would like to share some of the plugins I found after a bit research.

1. Add to Any: Share/Bookmark/Email Button

   Help readers share, save, bookmark, and email your posts and pages using any service, such as Facebook, Twitter, Digg, Delicious, and over 100 more social bookmarking and sharing sites. The button comes with AddToAny’s customizable Smart Menu, which places the services visitors use at the top of the menu, based on each visitor’s browsing history.
   Link to Add to Any

2. Admin Favicon

   Admin Favicon is a very simple plugin. It creates a link to a shortcut icon, or favicon, into the header of the Wordpress administrative console. What does this mean? Look at the address bar or tab indicator of your web browser. You should see an image next to the URL of this page. This is a favicon. It lets you easily identify this page from other pages you have open. This is very valuable for tabbed browsing, when you have many tabs open at the same time.
   Link to Admin Favicon

3. Advanced Permalinks

   Provides advanced permalink options that allow you to:
   Have multiple permalink structures. Permalinks can be assigned to posts or ranges of posts
   301 redirect old permalink structures (many structures are allowed)
   Category-specific permalinks. Posts in certain categories can be assigned a permalink structure
   No need to have a base to the category permalink!
   Change author permalinks
   Enable periods in permalinks – perfect for migrating old websites
   Link to Advanced Permalinks

4. Akismet

   Akismet checks your comments against the Akismet web service to see if they look like spam or not and lets you review the spam it catches under your blog’s “Comments” admin screen. Matt Mullenweg did a brilliant job on this plugin and it’s become a staple that every WordPress blog should use.
   Link to Akismet

5. Advertising Manager

   This plugin will manage and rotate your Google Adsense and other ads on your Wordpress blog. It automatically recognises many ad networks including Google Adsense, AdBrite, Adify, AdGridWork, Adpinion, Adroll, Chitika, Commission Junction, CrispAds, OpenX, ShoppingAds, Yahoo!PN, and WidgetBucks. Unsupported ad networks can be used as well.
   Link to Advertising Manager

6. All in One SEO Pack

   Optimizes your Wordpress blog for Search Engines (Search Engine Optimization).
   Link to All in One SEO Pack

7. Custom Post Order

   This is a simple plugin that enables users to modify the order in which posts are displayed on all pages(or in selected categories) of the blog. This is very useful when you have a blog in which you want to display posts in the order they were posted, from the first post being the oldest one, to the last post which is the most recent one, or the other way around. The options provided with the plugin at this moment allow users to order the displayed posts by post date, post title, post author, last time modified and post slug, either ascending or descending.
   Link to Custom Post Order

8. FT Signature Manager

   This simple little plugin gives each author on your blog the ability to setup a signature and to include it at the bottom of their posts.

   The admin screen gives each author the ability to format their signature (a text area with HTML formatting enabled) and to indicate whether or not they want the signature on or off by default.
   Link to FT Signature Manager

9. Post Avatar

   This plugin simplifies including a picture when writing posts by allowing the user to choose from a predefined list of images. The image can be automatically shown on the page or output customized with the use of a template tag in themes. This plugin is similar to Livejournal userpics. Developed with Dominik Menke.
   Link to Post Avatar

10. Publish To Facebook

    Publishes posts, pages or both to your Facebook Mini-Feed directly from Wordpress.
    Link to Publish To Facebook

11. Simple Tags

    Simple Tags is the successor of Simple Tagging Plugin This is THE perfect tool to manage perfeclty your WP 2.3, 2.5, 2.6, 2.7 and 2.8 tags

    It was written with this philosophy : best performances, more secured and brings a lot of new functions.
    Link to Simple Tags

12. Sidebar Widgets

    It’s called Sidebar Widgets because it allows you to move things (widgets) around, in and out of your sidebar. A widget is something that you might want on your sidebar, such as a category list or the most recent comments or a link to your admin pages. There is even a widget that lets you type whatever you want in the sidebar, such as some HTML or Javascript code.
    Link to Sidebar Widgets

13. Subscribe to Comments

    Subscribe to Comments is a robust plugin that enables commenters to sign up for e-mail notification of subsequent entries. The plugin includes a full-featured subscription manager that your commenters can use to unsubscribe to certain posts, block all notifications, or even change their notification e-mail address!
    Link to Subscribe to Comments

14. Sociable

    Automatically add links to your favorite social bookmarking sites on your posts, pages and in your RSS feed. You can choose from 99 different social bookmarking sites! WordPress 2.6 or above is required, if you use an older version, please download this version, please keep in mind that version is not maintained.
    Link to Sociable

Cheers!!
Joginder Poswal