What I found worked for me were simple sorting rules in just about any semi-real email client. Create a spam folder, and then create a bunch of filters based on the spam you've already gotten. (from addresses, viagra, mortgage, "long distance") Then, filter out everything that doesn't have your email address in the To or CC fields. By this point, you'll have cut down tremendously on what makes it to your real inbox. Now, every time a piece of spam gets through, you spend a minute thinking of a rule that would have caught it.

There are more complex systems, but this is what I've found works for me.

Matthew