"Anxiety is a super-lightweight To-do list application for Mac OS X Leopard that synchronizes with iCal and Mail. Its aim is to provide a streamlined, easily accessible interface to add and check off your tasks ... Anxiety utilizes Leopard's Calendar Store to remain in sync with iCal and Mail. Add, remove, or check off a task in either Anxiety or one of these apps, and the changes will be reflected in the others."

Anxiety can be toggled on or off via a menubar item and can float above other windows or subtly fade out when you switch applications.

A GTD workflow diagram created by Scott Moehring

http://www.freelinereport.com

Being organized is a significant element of success for any businessperson. With technology rapidly advancing, sound recorders are becoming very popular, thus eliminating the need for physical note taking. It can, however, be quite beneficial to take notes with the right notepad. By taking notes, you ensure that your thoughts and to-do lists are well organized, making it easier to keep up with a hectic schedule.

Although ZTD is a much simpler system than GTD, the basics are the same. Zenhabits has a very long list of GTD resources that will be valuable to anyone using the original GTD system or one of its variants. You can also adapt the tips and tricks mentioned in the resources to ZTD or your own customized productivity system.