Panniers, by and large, are not the best suited for hauling heavy things (like 4" thick 14 pound medical textbooks).

How about a basket? For about twenty bucks, you could get a cruiser-cool remove-able wire front basket that could easily carry all of your stuff. Top it off with a net-bungee and you're good to go.

Or, if you've got a LOT of stuff (say all your books, your laptop, and two bags of groceries), you could go for the wire double-rear baskets. Even more dorky than the front one, but very utilitarian.

If it were me, I'd go for the front one. Then, you can just drop your backpack in the backet, pull the net over the top, and roll. Cheap, easy, and if it's been a particularly long day, you can always wear the backpack so that there's room in the basket for beer.