As a former Outlook user I have been surprised by the lack of good To Do lists, or task managers, among the profusion of Web 2.o applications that have been in our collective face in the past few years.
It's pretty incredible, all manner of music recommendation services (cough...) but such a paucity of something so basic, and so comparatively easy to develop.
Yahoo! Calendar does have a task list, but it is very basic, hardly a task manager. The interface is not very slick either. Google Calendar, which otherwise has a superb interface, doesn't even have a task list to begin with.
All the buzz (ya, that inescapable buzz) over the past year seems to be about Remember The Milk... people talk about it as if it is the Second Coming, or Obama. But a glaring shortcoming is the lack of sub-tasks, or task hierarchies.
A new find is Todoist. Finally something with a nice friendly interface and a task hierarchy! It still could use some work, like a calendar view. Another thing, tasks are inextricably tied with appointments and schedules, so I'm surprised that both Remember The Milk and Todoist are not schedulers-come-task-managers. It seems like a no-brainer to me that two genres of application really belong together. I think there is a genre called PIM (personal information manager) that does encompass both. Remember The Milk tries to piggyback itself on Google Calendar, but it is not a very smooth or seamless operation.
Anywhoo, for now I will continue to test-drive Todoist and let you know how things are going!