I've found a really effective way of managing my email, assuming you are running Outlook 2010... This is how its done.
Create 4 folders:
-Action Required
-Action Personal
-Follow Up/Waiting
-Closed
When a message hits your inbox, use a quick step to move it to one of the appropriate 4 folders. Do not file mail. Anything you would file, send to the Closed Folder. The Closed folder is indexed by Outlook 2010. If you learn how to search properly in outlook, it becomes second nature causing Filing with 300 subfolders to be obsolete. Work from your Action Required folder or Action Personal, and keep an eye on messages in the follow up/waiting folder for things you may be partially responsible for or are waiting on. Everytime you read an email, put it in one of the 4 folder or delete it. Add a few rules to automate things and you are set and email is no longer a burden. Its that simple.