I'm starting medical school in the fall and would like to be able to use the iPad in place of a Tablet PC to view and edit large 500+ page PDF documents. I need to be able to highlight, annotate with text boxes, and free draw figures on the PDFs. I also need to be able to save and export them for viewing on a PC or Mac. If any iPad users on here have experience with some apps that will work for this purpose, please let me know. I am drawn to the iPad for the battery life and simplicity. Other than PDF editing, all I need is internet access and I'm set. Thanks all.