I don't do insulated jackets anymore - layering with a shell is much more effective, though probably not ideal for walking around campus - so I don't have any specific model recommendations. But it shouldn't be hard to find on your own, if you know the properties you're looking for.
Down offers the highest warmth-to-weight ratio of any insulation, so it's a natural (literally and figuratively) way to go. It's also expensive, but worth the money if you're looking for a lightweight, warm jacket. You could also go with synthetic insulation like Primaloft if you want to save some money.
You don't mention if you need it to be waterproof, but I would suggest it. This way if it's rain or wet snow, your down doesn't get all soppy (down's one negative is that it's ineffective when wet). Waterproof also means windproof, so it will give you protection from any blustery gusts.
Since a given semester incorporates a lot of weather, I'd consider something with removable down insulation. This way you can go full-on winter mode or have a lighter, waterproof jacket and non-waterproof down liner for late winter/early spring. Something like this:
That's out of stock, but gives you an idea. Just browse or search for 'waterproof jackets with removable down liners' or '3-in-1 jackets' (shell, liner, insulated shell) and you should find some others.
In fact, here's a whole section on Backcountry.
Second Sierra Trading Post for great deals on jackets (unless you're a fashion hound that needs the latest, flashiest model).