I host my own email (and that associated with all the domains I manage), and therefore have to deal with the issue of spam. My spam filter currently catches between 500 and 600 messages a day, and misses around 50 spam messages.
While it is pretty accurate, I do feel I need to personally review the spam mailbox before deleting messages, as somewhere around 1 in 5000 messages tagged as spam are legitimate. I've taken different approaches to this review, but currently sort all messages by subject and then can quickly page through messages with identical or similar subject lines. For example, currently in the hopper:
I have been using SpamAssassin for a number of years and have been quite happy with it. It would presumably be even more effective if I had a more current version of the filters.
But I am getting very tempted to move to a challenge response system, as annoying as they are. I'm just spending too much of my precious time combing through the spam box.