Here is a suggestion for those doing development, something very powerful and incredibly useful in the fight against comment spammers, ping bots, and other annoyances:
my suggestion is creating a new folder called wp-interactive and putting things like the wo-comments, wp-trackback, and any other similar code into this folder. The reason and logic is pretty simple:
htaccess is a common way to control access to a folder and the code within it. From simple restrictions such as denying an IP or range of IPs to using GeoIP software to limit country access, you could quite dramatically limit the amount of comment spam and such coming from certain places. So as an example, one might choose to allow users from places like Russia, Ukraine (two separate countries!), or China to read your blog, but you might block them from posting comments, sending ping backs, or accessing any other things that could create spam or problems on your site.
You could even conceivably move wp-login to this location, which would again allow for more security in this situation, and make it easier to stop the endless door knocking of people trying to access wordpress blogs.
In a more fancy version, it might even be worth having an admin page that would allow you to block IP ranges or even go to the extreme of automatically blocking IPs which send spam comments from having access to the comments processing.
It's time to take action on these important security issues.