This seems to be a good way to combat spam. Disable your comments and add one of these contact forms into any posts you would like visitors to be able to still contact you about the post. Very simple to install and comes with a spam free contact form which can be added to any page by pasting the spamfree-contact tag.  You can download the plugin at http://wordpress.org/extend/plugins/wp-spamfree/

It’s a compilation of all tags used in your blog. When clicked, it links to corresponding articles containing that tag. Pretty cool! Check it out at http://wordpress.org/extend/plugins/wp-cumulus/