I am still an agnostic with reference to my office productivity methods. I switch back and forth, at times meandering lost in the wilderness. I move from post-its to notebooks to on screen solutions including iGTD, iCal and/or plain text files (though a constant there is that Quicksilver always plays some role). One could waste alot of time figuring out how they'd like to manage their time.
I did find helpful this article on 5 Amazing Mac Apps for Getting Things Done (from Zen Habits).
"The ideal for anyone interested in Getting Things Done (more on GTD, and more)– or just being productive and organized, for that matter — is to be able to quickly add things to your to-do lists without interrupting your work; to be able to see what you need to do right now, without worrying about everything else; to be able to organize stuff without too much work."Do share in the comments any tips, methods, utilities you use. The choices really are legion.