My spam has gone down as well, but mostly due to my own policies. I use the trick of drakino_whatever @ miniinfo.net for things, and if one address starts getting spam more then anything else, it gets blocked at the server.

I don't trust a lot of the blacklists that accept submissions from everyone without review. I found it was blocking legitimate things like billing statements from MMOs, because the same servers distribute MMO gaming newsletters that one person marked as spam instead of unsubscribing from. I use one blacklist on my server that definitely only stops spam, but it honestly blocks maybe 10% of the traffic that my personal blacklist does.

I still despise any method that generates more work for the people sending e-mail, like the users who insist that I must click a link before approving their e-mail. If everyone switches to such an annoying system, no-one would get any e-mail, since the response to approve it would be met with a "you must approve this" and start a viscous cycle.