One thing I love about using iPads in my classroom is the ability to reduce paper how much paper we consume. I fill my class Dropbox with graphic organizers and activity sheets and have my students complete them on their iPads. PaperPort Notes is a great app for importing PDF files from Dropbox and adding text. My students will annotate the document and email it to me. I can decide what to print and display after looking at their work. The rest I can leave in my inbox and I know where it is if I need to reference it.
Check out my teacher store for lesson plans with activity sheets that can be completed on iPads!