I rely heavily on the "snooze" feature for email. I try to keep my inbox completely clear, and if something comes in that I can't deal with immediately, I snooze it for when I have time or it becomes relevant. I basically see emails as tasks, and they are completed (archived) when I've both performed the required action (maybe just read it, or sometimes also do something else) and responded if necessary. They can also act as reminders, such as maybe I have a meeting in a month, so I'll snooze it until a week before the meeting. This way I never miss any emails and respond in a timely manner to urgent ones. Snooze acts pretty much as a (sorted) queue.