Viira’s GTD (Get Things Done) app is based on the best selling New York Times book. The app works with your email, calendar and task apps, to best manage the tasks you need to “get done.” Recently, the app was updated to version 2.1, with project delegation and keypad shortcuts.
The GTD app works offline, which is helpful for adding tasks when in a basement or out of coverage. The app is also available with a free 21-day trial, so you can see how it affects your ability to get things done, before you purchase. Since this app is fairly pricey, I would definitely recommend the free trial first.