This was a silly mistake on my part, but it drove me crazy… I was debugging a simple workflow that was supposed to start upon item creation or modification. However, when I triggered an event that should have started the workflow, nothing would happen. Silly me - I was logged in as a user that was a farm admin, so my actions were logged by SharePoint as being performed by System Account. As a neat feature (though it felt like a bug today!), System initiated changes/additions don't trigger workflows. This is really useful if you need to come through and clean or move data without triggering notifications or other workflow items.
Nice reminder to use specified privileged AD accounts as farm admins, and not specific users.