A blog post from a few months back provides some great sense around managing email overload.
Here it is, in three sentences.
Step 1. Move all your action items out of the inbox, and onto a todo list. (The inbox was never designed to manage todos, which need dates, priority ranking, categories, and the ability to edit the text inside. No email program allows all of this.)
Step 2. Archive (or delete) everything else from the inbox. You can always search for anything you need to retrieve.
Step 3. Work from your todo list, not the inbox. After steps 1 and 2 the inbox will be totally empty, so this will be easy to do.
Aaaand that’s it. Three steps and you have an empty inbox. After the first time, you can accomplish steps 1 and 2 once a day – you might do it in the morning, or last thing in the evening – within a few minutes.
I’m thinking about writing an ebook along these lines: would that be useful?