My wife started me on the Report as Spam for AOL, and it has cut down my spam. . .but I've got one account that still gets, I dunno, maybe 20-30 a day. I don't count it, it just sits there.
I had a netzero account that I forgot about, and when I finally logged back in, the spam was down. Not as bad as before, but still there.
Considering on how I use my accounts, I have come to the conclusion that the broader you use an account, the more spam you get. I use my Yahoo for personal email, job searches (You'd think I get a lot off of that, but I don't) and Civ3 stuff (yahoo groups and notification for CFC), and get very little spam. My netzero, AOL and Hotmail accounts I was subscribed to a bunch of newsletters, and that's where all my spam came from.
I get two newsletters on Yahoo, but they don't give out the email, so it works out okay.