Current stats across all my email accounts: 115 spams/day, 30 of them caught by Mac Os X’s Junk filtering, 85 ended up in my Quarantine folder (people who aren’t in my address book or email history).
Best news: 0 false positives in the most recent ten days worth of email. By its nature, the Quarantine folder will occasionally contain real email from someone who’s trying to reach me for the first time, but I have a variety of other rules that do a pretty good job of detecting common cases. I also create custom addresses for every new vendor and site membership, and a monthly disposable address for this blog, and all of those get filtered into special folders.
I haven’t set up anything more sophisticated, largely because the problem is under control. About twice a month, something makes it into my real Inbox, and that’s not worth the effort.