I know most of you have personal choices when it comes to plugins so I would really like to know which according to you are the most essential Wordpress Plugins for your blog.
W3 Total Cache. A cache plugin is a must for any wordpress blog since it will reduce the load to the server. I also think a good seo plugin like Wordpress SEO by Yoast if you are trying to rank your site in search engines.
I don't think there is just one particular plugin as such. There are so many plugins without which I would not get the same experience as of now.
One plug-in is not enough. I always setup the WordPress SEO by Yoast and W3 Total Cache plug-in in a new blog.
I like the Contact 7 plugin for contact forms. The form integrates really well into the pages and you can have multiple forms set up which can go to any email address, as well as customise what content is in each of the emails. I use this one of my sites to allow my readers to contact my advertisers directly from the page rather than either contacting me or struggling to get hold of the supplier directly.
w3 cache - Speeds up your site. VaultPress - Backs up your site every hour. Gravity Forms - Best contact form plugin. ILWP Simple Link Cloaker - For cloaking affiliate links. Login Lockdown - For discouraging unauthorised access. WP Smush.it - For compressing images.
Here's a few I install on all my sites (all freebies): All in one SEO (my SEO optimization plugin of choice) Contact Form 7 (great contact form solution) Exec-PHP (execute PHP in posts and widgets) Google Analytics for WordPress (Google Analytics code insertion) Google XML sitemaps (sitemap generation, not just for google!) Stylesheet per page (ability to add a stylesheet per page/post/category/IE only/IOS only) Really Simple CAPTCHA (captcha code for CF7) WP-Syntax (for code snippet displaying)