I've been getting tons of spam that gets through our office's SpamAssasin filter. This was brought home to me big time after being away from the internet for 10 days. I was faced with almost 300 emails - mostly spam to plough through.
Apple Mail's spam filter is good if it has something to munch on, but these messages have one big gif image and then a random few lines of text from a story.
I created this little mail rule to filter them and it works nicely. Note that I get mail from several servers so I only do this filtering on mail direct to the office server.
I check the Junk folder and if there's somebody there I do want to get mail from I simply right click their name and "Add to Address Book".