I used Evernote for taking notes whilst reading, and a pen and paper for seminars and lectures. I tried using a Bluetooth keyboard with my iPhone running the Evernote app, but it didn't really work out as well as I'd hoped, so I just started taking my laptop with me again.
Pages was pretty good for typing up essays and reviewing trackback changes for draft chapters of my dissertation, but with my MA thesis (which was much longer) I really wished I'd used something like Scrivener from the very start.
I also found Prizmo to be pretty handy for my iPhone for collecting quotations from books and articles *you take a photo of the page(s) using the phone's camera, and the app can then optimise the image, run an OCR process to convert it to text and then save it to Evernote.