Found some good advice on e-mail management:

Managing e-mail realistically

It might seem strange, that someone who is an advocate of e-mail marketing is linking you to someone who advocates deleting anything that even looks like a marketing e-mail.

In his own words:

If I’m likely to care about it, someone I like more than you will tell me about it.

But that’s the challenge – be the person that the customer likes more. If you’re marketing by e-mail even semi-regularly, you should be trying to build a relationship. Make your e-mail one the customer wants to read, even if it does involve a pitch.

The way I see it, if the customer doesn’t want to read my e-mail, I should be writing better e-mails. The best place for e-mails you don’t want to read – even if they’re from me – is the trash folder.