An excellent presentation from Merlin Mann on how to deal with e-mail and have an inbox with zero e-mail in it!

Learn how to Manage your Email.

-Archive / Delete. Just Delete it if you can.

-Delegate. Can you forward it to someone?

-Respond. if less then 3 minutes of your time.

-Refer.

-Do. If you can do it now go do it.

Keep your sanity and learn how to manage email.