this is a pet peeve of mine, but there is nothing more tired than the symbol of che, a lot of people dont seem to understand who he was and what he did. the irony of mass produced consumer items (probably in some 3rd world sweat shop) with his image emblazoned on it, being purchased by ill informed sheep (no offense) makes me roll my eyes, and makes him probably turn in his grave.
i remember a few years back the leader of a student "peace protest" wearing a t-shirt with che guevara on it. he is noted for many things, but being peaceful is not one of them. he killed a lot of people, and was partly responsible for the (continued) poverty and opression of a lot more.
anyway, bags are so passe! get a locker and keep your stuff there, then only take the books you need for each class.