I could spend all day in the UW bookstore (and have come close before!).
In addition to textbooks and everything-you-ever-wanted-with-Bucky-the-Badger-on-it, they have a great selection of art supplies, pens, and random cool gift things. I love trying out all of the pens. It used to be one of my favorite things to do when a new semester would start. I would reward myself with new pens for surviving the hell that is textbook purchasing.
The bookstore also has a great selection of used books for cheap. So now I can buy back all those books I wished I hadn't sold back to the bookstore to buy ramen.