Depending on how much you need to sort, plastic drawers could be the perfect solution. I currently have my math units sorted / stored this way. Each skill has it's own drawer. Inside you'll find hardcopies of all of my resources relating to that skill, games that I've made, related children's literature, and my transparencies for teaching that skill.
I really like this method because the drawers slide out all the way. I can easily carry the drawer to my desk or a table when planning.
I used to store all of my reading materials this way as well. However, my district adopted a new reading program a couple of years ago and it came with so much stuff! Come back next Monday to see how I organize those resources.