I use goodreader on the iPad the same way you use textbooks. Only on the PDFs, but you can type, highlight, write, scribble draw all over the PDF. One feature t

I use goodreader on the iPad the same way you use textbooks. Only on the PDFs, but you can type, highlight, write, scribble draw all over the PDF. One feature that I like is I can then export just the typed up notes, so I have my own kind of cliff notes version of a book. Good if you follow the 'How to read a book' methodology.