Since I moved to GMail I don't know what spam is anymore: everytime people complain about spam I'm confuzzabled because I honestly thought the issue was solved.
It's great to run your own mailserver and be independant of the evil Google etc. but face the facts: people on GMail hardly get spam anymore...
Now as to how to fight spammers I'd suggest building a gigantic botnet, taking control of hundreds of thousands of credit cards numbers and ordering like mad from these spammers. Make it so big that credit cards companies start noticing the issue.
This of course should be done by someone who doesn't care about petty money...