Here are a list of Apps for doing the basic MSOffice tasks and more:

Pages/Keynote/Numbers

Apple's version of Office. Works very well on the iPad and you can work with and export as Office documents. Formatting doesn't always work. If you only get 1, get Keynote. Quite expensive at £6.99 an app. Evernote is free (explained on the Collaboration page).
Keynote is a good investment if you want to create Powerpoints on the iPad.

Cloud On

a free app that lets you edit office documents. Syncs with Dropbox
Documents Free is also worth considering.

Docs To Go, Smart Office Quick Office

The last is expensive but recommended. All will allow you to create and edit Office Documents.
Perhaps the most cost effective option is Office2 HDat £5.99
Office 2 HD.jpeg

Here is another opinion on Office Apps that considers many of these apps: Appspicker top 6

Basic Word Processing

Notes comes ready installed is fine but lacks organisational ability. Free apps like PlainText and Evernote let you create folders, but also automatically sync to Dropbox. IA Writer is a really good basic word processing app.

Notemaking

These really start to show off what an iPad can do. Try Noteability for 69p. Evernote is free and syncs your notes as well. This is turning out to be the preferred option for the students.

PDF Readers and File Managers

Adobe Reader is Free .GoodReader is highly recommended at £2.99. Excellent for going through/ annotating/highlighting past papers etc. Works well with iCloud and Dropbox.
PDF Expert has the edge though for actually working with PDFs.
Documents by Readdle is free and at manages files in a variety of formats.
Files App has a brilliant interface that allows drag and drop from your PC to your iPad and vice versa.
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