"Wunderlist HD for iPad will boost your productivity. Organize your to-do lists on the go and synchronize them with your free Wunderlist account. View and modify your tasks on Windows, Mac, Linux, iPhone/iPod Touch, Android and the web."
"Evernote is an easy-to-use, free app that helps you remember everything across all of the devices you use. Stay organized, save your ideas and improve productivity. Evernote lets you take notes, capture photos, create to-do lists, record voice reminders"
"Dropbox lets you bring all your photos, docs, and videos anywhere and share them easily. Access any file you save to your Dropbox from all your computers, iPhone, iPad and even the Dropbox website!"
4- Google Drive
"Get started with 5GB for free to safely keep all your stuff in one place and then access it from any device, anywhere. Store documents, pictures, or other files - even the big ones - using Google Drive and easily share them with anyone. "
5- Errands To do-list
"Errands is a task manager with a pleasing design and is easy to learn and use. Crafted with a blend of basic and advanced features: Folders, Checklists, Task Images, Scheduling & Repeating, Alerts (alarms), Automatic Badge Updating, Calendar View, Mail Tasks, Multiple View Modes, Search and more!"
6- iStudiez Pro
"A student's life is a dizzying mix of activity and just plain craziness! Take charge of your schedule and put iStudiez Pro to work for you! Take advantage of iStudiez Pro easy navigation and never miss another course, lecture and lab, track tasks and deadlines, plan homework, arrange assignments and much more!"
7- Orchestra To-Do
"Orchestra is an amazing to-do list app that helps you stay organized with reminders, recurring tasks, real-time sync and voice capture. But the real power behind Orchestra is how it connects your colleagues, family and friends to get more done."
"Toodledo is a powerful task and note manager, for the iPhone and iPad. It will organize your to-do list and notes, and make you more productive. You can use Toodledo as a standalone application, or you can synchronize with Toodledo.com, one of the most popular online task managers"
"Millions use Any.DO every day to remember all the things they want to do and make sure to get it done. Key features: Seamless cloud sync, Speech recognition, Time & Location Reminders, Folders, Notes, Repeating Tasks, Calendar view, Gesture support & more! "
10- To Do's Lite
"For the important events, such as meetings, business events, important meals, and loads more, you are going to have the option to choose between the priority of the events!! Like this, you are just not going to miss them, but you will know which ones must be done and attended with higher importance!"