I've been using Todoist for a while, and am very satisfied with it. It can integrate with google calendar, it's very easy to add tasks and date, and the free v

I've been using Todoist for a while, and am very satisfied with it. It can integrate with google calendar, it's very easy to add tasks and date, and the free version is sufficient for most uses. It also supports sub-tasks, although I don't use it personally.