GTD (Getting Things Done)

(Image credit from The New Shelton.)

I'm trying to be more productive with my time throughout the day. I've become a big fan of a couple of sites, Lifehacker and Unclutterer, that really appeal to my OCD side. Of some of the many things that have been suggested to GTD (Get Things Done), email has been tapped as being the source of the least AND most productivity. It's all a matter in how it's used. I don't remember the link, but the study was done with people completing tasks under different conditions and it turns out, in terms of accuracy and adjusted IQ, someone who is stoned is more productive and intelligent than someone who is "plugged in" all the time.

Since being "plugged in" doesn't have all the other benefits of the other option, I'm turning of my automatic email notification and only checking email once an hour. It will be a while before I can move to the suggested practice of doing email only twice a day at 11:00 and 4:00, but I've already noticed a huge difference in productivity by feeling that the most effective use of my time is not immediately responding to every email as they come in. I wonder, what are some practices that others use to GTD and get the clutter out of their lives?