There are currently over 9,000 plugins available for WordPress but the question is which ones are the best ones to use. Every one has their own list of what to use and how to use them. Below is a list of plugins that I have found to be the most useful:

1. AddToAny: Share/Bookmark/Email Button: Help readers share, bookmark, and email your posts and pages using any service
2. Advertising Manager: Control and arrange your Advertising and Referral blocks on your WordPress blog
3. All in One SEO Pack: Optimizes your WordPress blog for Search Engines
4. Apture: Makes it easy to add contextual images, videos, reference guides, links, maps, music, news, documents and books to your blog to create a connected media experience that keeps readers engaged on your site
5. Contact Form 7: A simple and flexible contact form.
6. DandyID Services: Retrieves your DandyID online identities and displays them as clickable links in your sidebar
7. Disqus Comment System: Replaces your WordPress comment system with your comments hosted and powered by Disqus
8. FeedBurner FeedSmith: Detects all ways to access your original WordPress feeds and redirects them to your FeedBurner feed so you can track every possible subscriber
   
9. Google XML Sitemaps: This plugin will generate a special XML sitemap which will help search engines like Google, Yahoo, Bing and Ask.com to better index your blog
10. Multi Column Category List: Displays a customizable list of categories in multiple columns.
11. Shadowbox JS: A javascript media viewer similar to Lightbox and Thickbox. Supports all types of media, not just images.
12. TweetMeme Retweet Button: Lets visitors retweet your blog posts
13. Twitter for WordPress: Displays your public Twitter messages
14. 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.
15. WordPress.com Stats: Tracks views, post/page views, referrers, and clicks.
16. WP-Cumulus: Displays a flash based tag cloud.
17. WP-PageNavi: Adds a more advanced paging navigation to your WordPress blog
18. WP-Stats-Dashboard: Displays the WordPress.com stats graph, your traffic and social metrics monitoring on your dashboard
19. WP Super Cache: Generates static html files from your dynamic WordPress blog. After a html file is generated your webserver will serve that file instead of processing the comparatively heavier and more expensive WordPress PHP scripts
20. Yet Another Related Posts Plugin: Returns a list of related entries based on a unique algorithm for display on your blog and RSS feeds. A templating feature allows customization of the display.

• Which plugins do you think are the best/use?
• Do you use any of the plug-ins listed above? If so, what are your thoughts on them?