List of the Best Captcha Plugins for WordPress 2012
WordPress is undoubtedly the best blogging platform and for that one reason its one of the most targeted framework by Spammers and spam bots. Its a default that you should be using the official spam assassin plugin called AKISMET and in addition to that using a Captcha plugin ensures you are least hit by these spam bots.
Below are the list of the best Captcha plugins that you can use on WordPress
These are all high quality plugins, however I would personally recommend the first two as your trusted captcha plugins. Mainly because ReCaptcha is official captcha plugin from Google and is a little sophisticated but very effective. If you are looking for a simple option, SI Captcha is a great plugin to try out. I personally use SI Captcha on this blog.