Wired magazine profiles productivity guru David Allen and offers a good summary of his Getting Things Done system, its history, and some great quotes from The David. First, for folks who say GTD is too complex:
[Allen]realises that his system can be difficult and that he's often accused of going overboard with elaborate schemes. He responds with a shrug. "Look, the workings of an automatic transmission are more complicated than a manual transmission," he says. "To simplify a complex event, you need a complex system."
The people willing to take on that complex system? They're the ones who know they need help and are trying to improve.
The book is for people who are striving hard. "The people who take to GTD are the most organised people," Allen says, "but they self-assess as the least organised, because they are well-enough organised to know that they are fucking up."