From the perspective of a psychology graduate student at a large university:
1) Get used to taking notes on a laptop via typing.
2) Use Preview to annotate lecture outlines; this works wonderfully (you can draw arrows, circle things, type notes, underline, highlight, etc)
3) For course involving mathematics, print available lecture slides or outlines, and then take notes with a pen and paper (i.e. right on the slides themselves).
Trying to find some way to use a tablet seems to just make things more complicated. A laptop is not too much more bulky, and has much more functionality and utility. True, you cannot hold it like a book and read from it on the bus. But, does one really want to read a 3-column academic journal article on a tablet or e-reader? I sure don't; I have tried and hate it. Do your serious studying and reading on the laptop, and add annotations and notes right to the pdf files of the journal articles.