43 Folders gives some more tips for wading through all that email:

1. Shut off auto-check - Either turn off automatic checking completely, or set it to something reasonable, like every 20 minutes or so. If you’re doing anything with new email more than every few minutes, you might want to rethink your approach. I’m sure that some of you working in North Korean missile silos need real-time email updates, but I encourage the rest of you to consider ganging your email activity into focused (maybe even timed) activity every hour or three. Process, tag, respond to the urgent ones, then get the hell back to work. (See also, NYT: You There, at the Computer: Pay Attention)
2. Pick off easy ones - If you can retire an email with a 1-2 line response (< 2 minutes; pref. 30 seconds), do it now. Remember: this is about action, not about cogitating and filing. Get it off your plate, and get back to work. On the other hand, don’t permit yourself to get caught up in composing an unnecessary 45-minute epistle (see next item).