It depends on your needs. But it helps to understand what the two words mean:   “Waterproof” means that water will not penetrate the material, or that the backpack is impervious to water. In short, a waterproof backpack means water can’t get inside the bag–unless it’s unzipped.   “Water-resistant” means that the material or product will repel some of the water, but not all of it. So, in some instances, like when there’s a very heavy rain, some water may seep through the material and into the backpack.  It’s important to know since you don’t want to get your laptop, camera gear or most other consumer electronics wet. Be sure to research your laptop backpacks so that it has the right type of material for your work or personal life.