One more item on ThemeClick.com on this category. Anti-spam Pro plugin blocks spam in comments.
Anti-spam Pro is powerful and extended version with settings of free and popular Anti-spam plugin – http://wordpress.org/plugins/anti-spam/
Anti-spam Pro ver.2.0 released with more powerful spam protection.
Anti-spam plugin blocks spam in comments automatically, invisibly for users and for admins.
No captcha, because spam is not users’ problem. No moderation queues, because spam is not administrators’ problem.
More info at – http://web-profile.com.ua/wordpress/plugins/anti-spam-pro/
We are sure after from the success installation from this item Anti-spam Pro to your website you will be very satisfied