Like you, I hate spam in all its forms -- email, mainly, but especially comment spam, which I've gotten bombarded with on my own blogs so badly that I've had to moderate all comments by hand. As it turns out, there is a plugin for Movable Type which can use blacklist lookups to block spambot addresses; I just hadn't been able to find the right RBL to use for it.
The best results so far seem to be from sbl-xbl.spamhaus.org, which tracks a great many IP addresses from known spambots. After I started using their RBL as my comment spam blacklist, the amount of spam I've been getting has plunged to nearly zero. Try it.
