1. Yoast WordPress SEO: This plugin allows you to achieve better SEO for ypur website.
2. Jetpack: This is a comparitively newer plugin that allows you to enable features like social network comments, CDN, URL shotener etc.
3. Google Analytics for WordPress: Want metadata from Google Analytics on your website? This is the plugin to use.
4. Better WP Security: This is a handy security tool that has a quick setup for protecting against attacks. In addition, advanced users can also implement advanced security options through this.
5. BackUpWordPress: This plugin can be used to backup your database by providing your own settings.
6. WP Smush.it: Images increase the loading time for your page. This plugin lowers the sizes of te images so as to make the page load faster.
7. MailPoet Newsletters: This plugin is useful if you’re sending newsletters etc. from your website. It posts automatic newsletters, auto responders and notifications.
8. Contact Form 7: This is perhaps the best option for creating contact forms on your website. It gives you a number of options and generates short codes for them.
9. Google XML Sitemaps: Sitemaps help search engines in better indexing your blog. This plugin can create XML sitemaps for your website.
10. TinyMCE Advanced: The TinyMCE plugin can be used for presenting visual editors on your website along with additional options.
11. WPtouch Mobile Plugin: This plugin helps you in making a website ready to suit the mobile market.