http://wordpress.org/extend/plugins/
http://wphacks.com/wordpress-plugins/
http://www.sitesketch101.com/15-incredible-wordpress-plugins-you-need
http://visionwidget.com/inspiration/web/465-best-wordpress-plugins-must-have.html
http://www.corebloggers.com/blog/best-wordpress-plugins-for-your-blog.html
http://www.quickonlinetips.com/archives/2007/12/best-wordpress-plugins-for-power-blogging/