The Mac was built for Getting Things Done.  Below are the most popular programs that run on a Mac.  Most already sync with the Iphone or will soon do so.  The following Mac Software programs are rated among the best.

• Things by Cultured Code won Best of Show at MacWorld 2009.  It follows David Allen's GTD principles yet provides powerful flexibility so that you can customize your experience.  Cultured Code also developed Things for the Iphone that syncs of Apple's Mobile Me and your desktop or laptop.

• OmniFocus works great as a GTD trusted system but can also be used to fit other task management styles. You can add or hide features such as start and due dates, time estimates and task recurrence based on how you manage your tasks. With the Perspectives feature you can easily restore customizations with the click of a button.  There is also an OmniFocus for Iphone that syncs with your desktop or laptop.

• Daylite by MarketCircle is more than a GTD Application.  Daylite leverages GTD principles which are integrted into a power software for small to medium size businesses that are looking for a Client Relationship Management program.  It integrates with Ical, Address Book and Apple Mail with strong customizable features.  Daylite Touch - Marketcircle's companion application for Daylite - also won Best of Show at Macworld 2009.  

• IGTD is a strong free software for Getting Things Done on your mac with syncing capabilities for your mobile phone.

• Midnight Inbox supports the entire framework of GTD, Midnight Inbox provides additional symbiotic tools such as reference topic filing of information, archiving of completed actions and lists. Realms and contexts to catagorize your activities into sensible groups. And direct interaction with iCal, Mail, and Safari to keep you productive.  This program is for GTD aficionados.  The program strictly follows all the principles.  If you are a GTD purest you might just love this app. The only downside - no mobile app.

Support Applications:

EverNote by Evernote Corporation is a powerful Inbox.  It allows you to make text, audio and picture notes on your desktop and via your Iphone or Windows Mobile device.  It is the best mobile capturing tool out there.

Mailtags allows you to tag e-mails, assign them to projects and create tasks and calendar events right from Apple Mail.  One application is for those e-mails that come in that require action or are "waiting for" items.  For example, you can create a tag called "waiting for" along with a smart folder called "waiting for" - as soon as you add the tag to the e-mail it will be moved automatically to the "waiting for" folder.  A great tool for supporting GTD!

You want to do more research?  Follow this link for a plethora of GTD apps for Macs and PCs.