As a recent college grad, my votes were for runtime, reliability, and size (and that's how I'd rank them in descending order).
Runtime - As stated above, a college student's light ought to last for a long time, whether for extended blackouts, long nighttime outings, whatever. A decent output is recommended, of course, but the light should ideally use an efficient emitter that's geared towards lasting many hours.
Reliability - In my experience, most use of flashlights by college students occurs when the light is absolutely needed, and can't easily be gone without. As such, it'd likely be a real pain to have the light fail. Plus, if the light is reliable, then the college student very likely won't have to replace the light, unless they're careless enough to lose it. So reliability is an economical advantage as well.
Size - While there is something to be said for the ease of finding a 3D Mag in an extremely messy dorm room, I'd say it's far more valuable to have a light that can be carried in a backpack, purse, or even pocket at all times. I didn't know many people in college who would carry a flashlight in their pocket everyday (aside from maybe a coin cell keychain light), but I think it's perfectly reasonable to expect the wise college student to stash a light in a backpack. As such, I'd recommend one- to two-cell lights. And on that note, CR123's will be more compact, but I'd recommend AA instead, since college students could find those much more easily. (In the end, something P1D size would be great, though even up to SF G2 size should be fine.)
Other considerations:
Price - I didn't vote for this one, as it really depends on who's buying the flashlight. If it's the student buying it for him- or herself, then yes, price would be a very important attribute. However, if it's a gift, then it's not an attribute that the student would have to worry about, and I'd recommend the giver just pick something in a price range that they're comfortable with.
Protection capability - For a general purpose flashlight I would recommend against such things as strike bezels, since they can seem unnecessarily like weapons (among other things). However, if the buyer/giver/whatever of the flashlight feels that the student will be in a potentially dangerous environment (e.g., a campus in a bad part of town), then the strike bezel may be a good feature. Really depends, though, and if in doubt, don't get the crennelations.
Rechargeables - Although most college students have the technical knowledge to be able to do such things as buckle seatbelts and recharge batteries, I wouldn't expect them to go to the effort. Some might, but in my experience (personal, as well as others I've known), things like recharging batteries get put off until you need them. And in the case of a flashlight being used during a power outage, it's already too late. Plus, self-discharge has often plagued my use of rechargeables, as they go unused and un-recharged for long enough to lose their charge, while primary cells would still have been fine. Now, I don't want to discourage the use of rechargeables, I just want to recommend against making a college student rely on them (i.e., if you give the student a light with NiMH cells to use most of the time, give them some regular cells as well, just in case).
Multi-modes - I would say this is a useful, though not obligatory, feature in a college student flashlight. If you have the opportunity, multiple modes/levels of light will be very handy, allowing the user to select how much light is necessary at the time (perhaps even with the benefit of improving runtime a bit). However, I still think a light with a single, mid-range level of brightness should work fine (chances are, the student won't miss the higher or lower levels with such a compromise light).