Here's a quick list of how I do it.
- I use Gmail. That takes spam out of the picture completely.
- I use **a lot of filters** in Gmail to filter mail into a lot of labels. Most of them contain messages that I never read unless there is some reason to.
- The only mail in my Inbox consists of messages I want to look at.
- When I read them, if they require some action, If I can do it or reply immediately, I do. The GTD rule is replies that take less than 2 minutes. I probably use a rule or more like if it takes less than 30 seconds.
- Otherwise, I click on More Actions, Add To Tasks, and that email message goes into my Tasks list, which I use for my GTD process.
That's it. With this approach my INBOX gets, I don't know, I'd guess maybe 100 messages a week. A lot of them are ads from vendors I actually do care about, so I click through them with just a glance.
I use this same approach for both work email and home email.
In the spirit of Gmail, I don't delete messages (usually). So far, after using Gmail since it began, that's not been a problem. The excellent search capability means it's not difficult to find and email message that I may need.