langwitches has written a great post on iPad fluency and has accompanied it with the graphic below. As you can see, the graphic is not rich in data but still succinctly and smartly crafted.
Here are some of the apps included in the graphic :
1- Apps for researching, importing, analyzing, evaluating, editing, citing..etc
Google Drive
2- Apps for file exchange
3- Apps for screencasting, creating, remixing, mindmapping, reflecting, blogging, demonstrating visual thinking...etc
4- Apps for sharing with teacher, peers or global audience
Here is the graphic which you can download in PDF format from HERE. Enjoy