TaskUnifier Pro is a capable cross-platform task manager which can organise your various "to dos", and synchronise them across your network, or with the services OrganiTask or Toodledo.
The program can organise your tasks (and subtasks) in task, note or calendar views. Tasks may be grouped and organised by the location where they'll be executed (@Home, @Work, @Store), a goal you're trying to achieve (Find new job) a context (what you need to execute the task) and more.
A useful "task template" feature simplifies the process of creating new tasks by recognising that you'll often be doing similar things, over and over again. Set up a template with predefined task values and you can then create new tasks with the minimum of hassle.
A smart Task Searcher tool creates and stores custom filters, making it easier to find the tasks you need.
There's an option to publish your tasks to Google Calendar, handy if you're working with others, and an automation feature where you can have TaskUnifier Pro perform some custom action when you change a task's status.
Please note, although it was once a commercial product, TaskUnifier Pro is now free. That's not as good as it sounds: the developer has made it free because he's not going to keep it maintained any more. There most likely won't be any significant new features, and bugs will generally go unfixed.
TaskUnifier Pro is a powerful product, but it's not going to be maintained any more, so probably isn't something you should rely for your day-to-day life.