Here’s a great article about the most popular plugins for WordPress. I use many of these on this site as well as client sites.
http://www.wptemplate.com/plugins/wordpress-most-popular-plugins.html
a collection of the inessential to some, and indispensable to others.
WordPress is the world’s most popular publishing platforms, and it’s currently estimated to power 17.6 per cent of all websites. It’s highly customisable, very easy to use and, probably the best part, it’s completely free, making it an obvious choice for anythong from a simple blog to an online design portfolio .