First off, make sure that you are not mandated to buy a particular laptop. Some places do, and you can't say no (sure you don't have to use it, but why buy something twice?). My med school did that and it was advantageous from a support standpoint, where the med school basically had staff to take care of any issues right away. The laptop was overpriced, but did come with a 4 year bumper-to-bumper warranty, which came in handy multiple times.
That being said, IMHO, portability and decent screen size (e.g. a 17" monster laptop would be as hard to work with as a 10" little netbook jobbie) along with decent battery life (most lecture halls will have power, but you'll want a couple of hours out of whatever battery you have just in case). We were mandated to a stylus-enabled laptop as well (HP series laptops). That was actually very handy for annotating images in PPT quickly. If I did it over, I would repeat that decision today. It also folded so that if I had a second monitor, I could have the laptop flat like a book but with a large screen right over it. Worked great for highlighting text (with pen on the tablet flat like a book) and then typing more detailed notes in the second screen. I had a docking station as well so that I could come home and quickly get dual monitors, networking, and real keyboard+mouse working quickly.
I did undergrad when the rare 486DX laptop could be seen and by the time I did med school, laptops were pervasive. The most important and productive feature for laptops over anything else is being able to electronically categorize and easily search your notes. I found it very important to have a desktop search program (Google Desktop back then) that let me quickly search for a term across all my classes. As part of this, I tried to make sure that every note I took was in some kindof searchable format (E.g. typed in the notes sections of ppt or in an Libreoffice (preferred due to autocomplete) or MS Word). We had objectives for every block and I would take those MS Word docs and make sure that I had answers to every objective typed out. Organizing the info is half the battle, so whatever platform you use, make sure you know how to use the searching app for that platform or buy one that works well (money well spent).
In terms of computers, I am not an HP shill, but in med school that is what we had and they worked well. I just bought a spectre x 360, and it has been good so far (although work paid 2k+ for it 🙂 The lower end envy series may be a low cost option to look at. Lenovo et al have probably similar features. I stay away from Dell (overpriced), Toshiba (crap), and Apple (overpriced, although as a linux guy, love the concept). Things are cheap enough that even a low end option probably will work fine, and if it breaks through usage, it would be easy to replace. Make sure you have a solid backup strategy in place or keep things (non-patient identifying of course) in the cloud.
Good luck and congrats on your future matriculation.
