Can Assigning Value to Email Reduce Your Stress?

I recently read an article entitled "The Problem Isn't Information Overload" by David Allen, the author of Getting Things Done. In it, Mr. Allen helps to narrow the definition of what truly causes us stress when our email inbox begins to overflow. He argues that it is not a matter of information overload, but one of being faced with too many decisions about the potential value of the information contained in each email.
The great take away for me was the need for developing a means for users to quickly discern the potential value of a communication, without having to read the entire communication, so that they could categorize the message into a value bucket. Those value buckets being something along the lines of:

1. I need to take action on this now.
2. I will need to take action on this in the future by a specific date/time.
3. There is some relevant reference material worth saving, file it away.
4. I can easily find this information myself should I need it in the future so it is okay to delete.
5. This has no value to me, delete it now.

Do you have other value buckets? If so, please share them with the community.
What is the minimum information you would need about an email to assign it a value bucket?
You can read David Allen's full article here.