I am 2 weeks into my Inbox Zero experiment. So far it is great! After having 300+ emails in my inbox on a regular basis, about a month ago I started trying to be more diligent about email and was able to get down to a steady state of 150. Inbox Zero got me over the top, and while I have not hit zero, I am under 10 on a regular basis. I feel much more in control of my email (rather than the other way around) and email is taking the same or less total amount of my time as before.
The 10 second version of "Inbox Zero"
Stop "reading" email and start processing it. If you open a message, you need to DO something with it: delete/archive, delegate/forward and delete/archive, respond and delete/archive, or add to "to do" list and delete/archive. The main point is to stop using your inbox as a "to do list" because you end up wasting time because your inbox is a messed up mix of things that need hours or days of work and stuff that needs a quick read or response. Re-reading all the messages that you read but did not process ruins your productivity. If you open the email, do something with it right then.
If you want to learn more, check out the slides below, or watch the original 2007 Inbox Zero Video.