I think one reason a lot of students prefer a backpack, is because they will need to carry their stuff around from class to class, once they get to school. Certainly, transferring stuff from a pannier to a backpack would be a hassle. My approach: My bike has a big side basket, and I stuff the entire backpack in there, with a carabiner clip or a strap made from an old innertube, to keep it from bouncing out while riding.