Spam is not only eating your bandwidth, it's potentially deadly -- sort of. Unfortunately, there's little really reasonable discussion about appropriate limits on commercial e-mail. Some say NONE is permissible, others (spammers) say they're willing do DIE over the issue, citing First Amendment rights.
My big problem is with spam that is fraudulent and/or pornographic. If I can identify the sender and I know what they're selling is real and legitimate, I don't think it's spam. I've had my head bitten off over this point of view by "zero tolerance" advocates. A little perspective, please.