I never unsubscribe or open unrecognized e-mails. I believe it only confirms that you have a valid e-mail address and you will, as a result, get more e-mails.
I built a filter to filter some of the more graphic e-mails. Words like "Viagra, prescription" and various others that I can't mention on DIS catch a lot of the garbage. The explicit e-mails infuriate me.