One of the most popular iPad apps geared toward personal organization is OmniFocus. At $39.99, it's not cheap, but according to App Advice, OmniFocus is an essential task management app. It organizes your tasks in a variety of ways, including by project (i.e., several related to-do items) or context (all of your at-home tasks, for example). The "forecast" option lets you see your day or week ahead at a glance, allowing you an overall picture of what needs to get done, as well as where and when it needs to happen. The app includes other nifty features like task searchability, voice notes and picture attachments. If you have OmniFocus on your Mac computer or iPhone, you can sync between devices, but it also works well as a standalone for your iPad.
If you've read any articles about personal productivity products, you've probably come across "GTD;" it's an acronym for Getting Things Done, a work-life management system created by David Allen, an executive coach and productivity guru. Those who have implemented this system credit it with helping them lead less stressful, more productive lives.