This wordpress plugin is awesome! It works flawlessly.
With almost no setup this plugin will filter all comment spam into the wordpress spam filter. When there is a spam comment posted it will go into the wordpress spam filter automatically instead of your main comment inbox Therefore wordpress will not send you a notification email, making your email inbox free of spam comments. The best thing about this plugin is that the user does not have to input any captcha or any extra fields.
I would recommend this plugin to anyone that gets any comment spam because this plugin is the most painless solution for both the webmaster, and the user.