I have to agree with you Rats. They make modding a forum a pain in the ass. I've had other forums in the past for my own sites that I've shut down as the bots outnumber the posters sometimes.
For this site, I check once or twice a day for new users that have registered. I look at their log in names and if they're 'suspicious', I check their email to see where they're from. If their a spammer, I ban their IP, then I delete them and their posts (which is why I ask that people don't respond to spam).
Then I check for new inactive users. These are people that have registered, but not completed the registration. Then I delete all the suspicious ones.
The one that spammed the site got registered and spammed after I had already cleared out a bunch this morning.
My business website was hacked earlier this year, and google had a warning up about my site within hours. Then it took me a few days to get the warning removed.
So yeah, Rats, I agree - spammers, bots and black hat hackers should be fucked up, but there's little that we can do about it.