I get a fair amount of spam. On some of my email addresses, over 100 spam messages per day. I use PopFile for my filtering and have been extremely pleased with its performance, and highly recommend it to anyone with a spam problem. It's straightforward to use and very accurate in my experience.
Additionally, at work, I have installed SpamAssassin on our servers, which does a very good job as well, though not quite as reliable as ~PopFile. They work well together though and the result is an entirely manageable level of spam getting through.