Wordpress CAPTCHA plugin

Hi,

I am looking for a plugin that displays CAPTCHA before a user posts a comment.

What plugin do you recommend/use?

Thanks in advance

 

You can use http://recaptcha.net/plugins/wordpress/ Recaptcha or the Simple Captcha... http://wordpress.org/extend/plugins/simple-captcha/

 

I use Math Comment Spam Protection. It doesn't stop trackback spam though.

 

Thanks a lot for the answers. Will try the plugins out.
Rep given.