I really appreciated this article because the process to learning about Getting Things Done (GTD) and then finding a cross-platform solution (Windows at work and Mac at home) were so similar to my own. If you're at all interested in improving your productivity and organization, then you should read this article and carefully consider reading the book and then adopting Nozbe.
I've been slowly but surely making my way through Getting Things Done by David Allen (I'm using the audiobook from Audible.com and listening with my iPhone during my commute). As I'm sure many others have, I wanted to find some software to help me apply what I'm learning. Nozbe has been an excellent fit for my style. This article provides a nice summary of one's experience becoming accustomed with the Getting Things Done philosophy and using Nozbe to live it.