Catherine Hainstock has put together a draft list of iPad apps for use with the e5 model. Have a look at her post here describing the process. A chart of the apps is also available.
Cool!
I remember working on history curriculum within my school, beholden to the 'pet' topics of my peers. With this kind of access to class work, it broadens the peer group hugely! Not to mention the multitude of variations within topics...