One thing I wish I'd had for lit reviews/notes is a "reMarkable" tablet. I'm in my third year now, so the $600 price tag's a little too much for me at this point, but I would seriously consider it were I to start again.
The tablet uses E-ink like a kindle and is super nice for marking up papers and saving all of your notes in PDF form. You can then synch them to the cloud and access from a computer.
In retrospect, this would have been a HUGE time saver (and I think it would have saved my eyes from reading so many papers on a computer screen) (and I think it would have saved a few trees from all the papers I've printed out). Since it's not a laptop as well, I believe there's less of a tendency to procrastinate on it with email or surfing the web.