I've been Getting Things Done long before it was cool to GTD. My method is simple: I keep my list of things to get done in my email Inbox. Once I get a thing done, I move it to a different folder, and I forget about it. This forces me to deal with incoming email at a very rapid pace. I either keep it in the Inbox because I know I'll work on it in the next few hours (or days), or I reply to it and I delete it, or I file it away, or I simply delete it. There are of course cases when my Inbox grows, but then I take drastic measures to reduce its size. I try to have no more than 25 messages in my Inbox at all times. OK, sometimes I have up to 50, but that's my limit.
Just thought I'd throw this out there in case it might help somebody in organizing their workload.