There has been a lot of hype recently over the new gesture based to-do app, Clear. Purely because the UI is beautiful and simple. It's a great blend of Windows Phone 7 tiles but iOS' gradients. The app enables you to simply build to-do tasks with gestural actions, such as swiping up, pinching and other types of gestures.
It is an amazing app but if you have an iPhone 4S I highly recommend you make Siri and Apple's reminders app do the work for you. I compiled a post on how to really take advantage of Siri and Apple's reminders app - How To Use Reminders & Siri Properly. The post covers everything which Clear already does but does even more, like location based reminders and inputting things to your calender. Also the great thing about Apple's reminders app is that it enables you to sync everything in the app between all your iOS devices, it even lets you compile lists with people. All of this without having to use your fingers much at all. So if you have an iPhone 4S there is no need for Clear.
However if you're using an iPhone 4, iPad or other type of iDevice I highly recommend trying out Clear.