Due to a rash of comment spam, I’ve had to turn on CAPTCHAs. I hope this holds the bad guys at bay for a while. My apologies for the new tone of distrust on the comment form.
For what it is worth, I’ve had very good anti-spam results with the combination of Akismet, Bad Behavior, Comment Timeout, and Link Limits. All are wordpress plugins, but there must be some MT equivalents. (Akismet, at least, has an MT version.)
By the way, ‘preview’ breaks your captcha- if I type the right string and hit ‘post’ I’m fine, but if I type the right string, hit preview, and then hit post, I get told I’ve typed the wrong string, as if it expects that I should solve a new/different captcha after viewing the preview.