For evening and night time I would recommend a small Xenon flashlight in the 60 -120 lumen range such as Surefire and Streamlight. I think Surefire has a high impact plastic version of their 2 x CR123 light that can take the 60 lumen or 120 lumen bulb for about $35.
I have a similar one from S&W that is rated at about 80 lumen. I tried it out on myself at arms length and wow! I was blinded for about a minute. Just a big black spot in from of me.
The best advice is to avoid getting into a compromised situation to begin with.
* If you go to a bar, don't drink yourself blind and don't depend on someone getting you home. Have 2-3 drinks, eat something and have some coffee before walking back. Make sure you are alert and able to react and be observant. knocking off drunks stumbling out of bars is probablyone of the easiest htis a thug can make.
* Don't walk through deserted areas of campus. Take a longer route if necessary if it means staying in a more public space.
* Looking obviously aware (not distracted by a book, video game, or drunk) and ready to act is one of the best deterrents unless a small gang is waiting to harass passersby. In that case you should see them early enough to detour.
* If confronted hit them in the eyes with your Xenon light to disorient them and have the spray ready to go.
* The light and spray should be used to delay and disorient them giving you time to beat an exit or detour. You have no idea what weapons they might have or how many backup buddies they have nearby. Don't engage on the place and timing of their choice. Get out of there.
The best thing is to be at a campus with less risk. The big state universities probably have the biggest risk. Anonymity, much more land to patrol, and less choosy about the characters they accept.
My two daughters made it safely through college. One attended a small private Christian college in British Columbia and the other a small private military college in Vermont. Both exercised good practices of walking with friends almost all the time, generally not getting wasted at the local bars and stumbling home. They also had pepper spray and good flashlights although they never had even close to a need to use them (except for aggressive geese which she didn't use it for).
The military academy has a lot of shooting enthusiasts and reserve or even active duty troops, so even though the policy is no firearms on campus they would do any THR gathering proud. Every cadet has a an M14 in their room. Yes, it is without a firing pin, but still pretty cool. Many of the upperclassmen have handguns and even AR15, sniper rifles (their job in the service), etc. in their trunks. They are also a very tight knit group so if one was attacked, especially one of the females there would be hell to pay. It would be very difficult to intrude on the campus and not be noticed.
Anyway, the best protection is prevention. Avoid compromising situations, stay alert and have a light, spray and maybe a ASP baton ready for use.
For the dorm room I would seriously consider having a locking footlocker with a firearm (you could probably get away with bolting it to the wall or floor in the closet). If you have a roommate, even if they are shooters, I would not tell them about having a firearm. You never know when a relative stranger may get in a tiff with you and turn you in. Just tell them you keep your electronics in there, or a delicate musical instrument or something. Or you're holding onto your dead aunt's fine china.
Being at college during a major disaster and/or civil unrest would not be good unarmed. You are at your most vulnerable at school and you spend most of the year there.
When I went to a larger state university I always had a folder on me. 
