Even if you plan on doing most of your studying in the library, I think it's important to have your desk organized for a few reasons. Firstly, you need somewhere to store all of your supplies for quick and easy access. Secondly, when it's -10 degrees out and snowing, you might not want to go to the library anymore...and you might want to study at your desk. But if you don't have a desk lamp...or supplies...you will really be in a bind.
Bigso™ Bright Stockholm Magazine File / Linus™ Desk Drawer Organizer / Studio 3B™ Architect's USB Desk Lamp / Power Strip / Pencil Cup
Some of my favorite school supplies come from The Container Store. If your desk has drawers or a hutch, utilize this space for your supplies and keep the actual desk top open to work. I recommend pencil cups, desk organizers, and magazine caddies for organization. I like the sleek look of acrylic organizers, and you can spice them up with a vinyl monogram decal, if you'd like! Mine acrylic supplies are monogrammed with gold block decals that I purchased from etsy.
You can use magazine files for more than magazines! I use them to store my folders and notebooks...one file for MWF classes and another for TR classes. This makes it easy for me to grab my books for classes, and additionally, it keeps them store upright...taking up less space!
Additionally, a good desk lamp and a power trip (or two!) are necessities. Make sure you get a surge protector power strip for your computer, and a few other power strips to use throughout your room. Dorm rooms do not have a lot of outlets, and you have to share, so bring your own!