Chaos Control
I find Chaos Control an excellent app for keeping track of all manner of tasks or notes. The Chaos Box for quickly noting ideas and then the Folder/Project/Task structure allows sufficient granularity to store those ideas as well as all all types of memos tasks and notes . I use Favourites a lot. I'm running Chaos Control on an old Andoid phone, on a newer iPhone as well as on a PC and they all sync perfectly.. Sending reminders to multiple calendars is easy and works well too if you want to see just what you've scheduled for that day (without seeing all the previous tasks that weren't finished earlier and that Chaos Control reminds you that you could do )