I've given up on my old spam-prevention system of (a) graylisting, (b) spamassassin, and (c) procmail. It was getting too hairy, and Lorna and I were both getting 20+ spams per day even after tuning all the Bayesian filters. So what to do?
It turns out that pobox.com (my longtime mail forwarder) has recently added Cloudmark support. Why is this good? Well, Cloudmark has worked fine if you're an Outlook user, or if you're a corporate user with a big domain, but it's not been so easy for the sort-of savvy single user. Pobox has been great at leading SPF and other efforts, but they haven't been 100% at stopping spam.
Pobox also recently introduced their "AllMail" feature, so you can point a whole domain at them. Now I'm able to forward all my mail through Cloudmark's spam filter, and it works so incredibly well.