I have a Patagonia Black Hole, 25l backpack. The part on your back is nice and cushioned, the rest is a waterproof material. The straps are more comfortable than the North face ones I've tried. However, you do get sweaty underneath it. It has a laptop sleeve inside and water bottle pockets outside. I'd reckon a bag with venting might be better to avoid being the sweaty/stinky kid in class....