A growing list of productivity apps for the iPad - add/vote your favorite here.
Evernote for iPad lets you make new text and audio notes, as well as view your existing Evernote content all with a swipe or tap of your finger.
GoodReader is the super-robust PDF reader for iPad, iPhone and iPod touch.
Things is a beautifully focused and amazingly intuitive task manager. Other todo applications either oversimplify or are too difficult to use. Things instead offers the perfect balance between ease of use and powerful features.
Very similar to Instapaper in concept, but better
iAnnotate is an elegant PDF reader and a powerful annotation tool
iAnnotate for iPad Get Productive and Paperless on the Go iAnnotate turns your tablet into a world-class productivity tool for reading, marking up, and sharing PDFs, Word documents, PowerPoint files, and images.
Similar to Things. Manage all your tasks, projects, and to-do's. Sort by specific category, type and place. Also wirelessy sync with your computer through "cloud" database.
Great outliner with notes in it. Wonderful simple UI.
Mindmapping, Vision Board app that will not disappoint
Great for work. Great for school. Popplet is a platform for your ideas. With Popplet you can capture your ideas, sort them visually, and collaborate with others in realtime. Quickly and easily!