The iPad application that has been of the most use to me to date has been using it to grade papers. I have my students upload their papers to the class Moodle site, download them to Dropbox using DownloadThemAll! (for the Firefox Browser), move them into the iAnnotate library, and then open them in iAnnotate.
I read and comment on them using iAnnotate, then email them to the students and to myself. (See Kristi Upson-Saia’s trick to making stamps for common comments — it is a big time saver!) I find that I use the post-it notes, ruler lines, and typewriter functions the most often. In the future I am going to have the students include a scoring sheet/matrix at the end of their paper, so I will have it in the same document as their paper or lab report. Alternatively, I may try having the scoring matrix a separate pdf or try DocsToGo.
There are two main reasons that this process on the iPad works well for me. The first is the convenience- on my iPad, I have all the papers from the class, so I can read and grade whenever and wherever I have time. No more lugging piles of papers around, and worrying about losing them. The papers are in Dropbox, so I don’t have to worry about losing them if I lose the iPad, or needing a wireless connection, once I’ve downloaded them onto my library. The second advantage is that I retain a record of their work, for future comparisons and for answering questions the students may have. The next step will be to have additional assignments, such as problem sets, uploaded as pdfs. This may require another step on the students’ part, such as scanning handwritten answers, but I suspect it is less of an obstacle for them than for me.