$5. Current version average rating: 4.5 stars Designed for iPhone, iPad
With iOS 5, Apple finally added a reminders/to-do app to its mobile devices. And though Apple's Reminders app has a cool GPS component, it still leaves something to be desired. Into the void comes Due, a simple but effective to-do app. Due just makes it easy to quickly create and customize a reminder. With a tap or two, you can create a reminder that repeats the same time and day every week; reschedule it; or share it via email or message with others. I also like the orderly list of to-do items it presents, in chronological order. If you have a Dropbox account, you can use it sync reminders between multiple devices.