SimpleTask is described as 'One thing that other to-do lists don't have is simplicity. SimpleTask for Mac brings both a beautiful interface and an unparalleled ease of use to your Mac' and is an app in the Office & Productivity category. There are more than 50 alternatives to SimpleTask for a variety of platforms, including Windows, Android, iPhone, Online / Web-based and Mac. The best alternative is Org mode, which is both free and Open Source. Other great apps like SimpleTask are Remember The Milk (Freemium), Google Tasks (Free), Things (Paid) and MyLifeOrganized (Freemium).
Take your tasks anywhere with this feature-packed application. See tasks located nearby, add and complete tasks on the go, organize upcoming tasks, and sync it all seamlessly with Remember The Milk. Desktop app available for Pro users. Very good integration in GMail!
Get more done with the Google Tasks mobile app. Manage, capture, and edit your tasks from anywhere, at anytime, with to-dos that sync across all your devices. Integrations with Gmail and Google Calendar help you get tasks done—faster.
MyLifeOrganized (MLO) is a personal task outliner and to-do list manager which will help you to organize your goals, projects and tasks into a tree. The To-Do list with actions that require immediate attention will be generated.
2Do lets you take a completely different approach to managing your tasks. With its extremely simple-to-use interface and a comprehensive and flexible set of powerful features, it lets you focus on what's most important to you: your life.
Nirvana is a secure, cloud-based GTD® task manager accessible from your desktop web browser and mobile devices. If you have more to do than you can manage in your head, or if you want greater clarity of mind and focus in life, Nirvana is for you.
Simple GTD application to manage your tasks and to-dos. Syncs with web server. Complete with the usual Inbox, Today, Next, Tomorrow, Scheduled and Someday "buckets" as most GTD programs have. You can also create Projects for tasks with multiple steps.