Thanks to a tip from David Esrati (who I'm not going to link to from this post because I'm taunting spammers and don't want to inflict collateral damage on him), I'm testing out WP-SpamFree which is a really interesting antispam plugin for WordPress. I've used Akismet and Mollom before, and I've always been uncomfortable with externally hosted antispam systems. For some reason, I'm just not completely comfortable with relying on another server for this. I'd used Spam Karma 2 with great success, but since that went defunct I abandoned it as well.
Now, WP-SpamFree seems to offer an intelligent antispam system without relying on external servers or blacklists. I'm giving it a shot. So far, it's been pretty successful.
Let's see how well it does. Bring it.