If the notion of flagging your emails for better organisation grabs you and you're also a fan of Getting Things Done (as much of Team Lifehacker is), you might want to take a look at Pay It Forward Email Management, a system designed by three Microsoft techies for hyper-efficient email and task management. There's a training document for OneNote users included in the linked post, but the basics are pretty simple, as co-creator Ian Palangio explains:
PIFEM uses the out of the box Outlook 2007 features of flagging and categories to manage emails that you don't want to action/complete immediately. Once you date/time flag an item it is no longer clogging up your brain with secondary thoughts. If you manage it well... you can eliminate a lot of distractions from email, and focus on your highest priority items with laser focus.
The "Pay It Forward" reference links to the idea that if the approach works for you, then you should teach others to use it. If you've tried this (or a similar) approach, let us know how it goes for you in the comments. Thanks Ian!