Generally you cant block spam emails as they tend to come from different places (no one single email address).
As you say, WRONG to unsubscribe as it just lets them know the email address is live and being used so you will get MORE spam.
I have an email address that is only used to contact my immediate family but a few months ago I began to get spam and I now get about 30 a day, which all go in to my spam folder.
They are almost all American based (American companies etc) so it is a pain in the b*m.
It is getting so annoying I am thinking of setting up another email address just to contact my family , even though all the junk mail goes into my spam folder.
I keep hoping that somebody will "catch" these spammers and the spam will stop but it has been going on for months now.
Ba****ds!