When I first got out of college I long-termed subbed in an art classroom that had storage shelves that were on a track hung from the ceiling. There were probably 5 double-sided shelving units that could be pushed together. When you needed to get to something you pushed the units open creating a pathway inbetween the storage units. It was such a space saver and had so much storage. If I ever get to help design my own room, I would definitely do something similar.
Also, I agree with the others that mentioned the Smartboard. It has been the most motivating and visual tool I have ever had. I LOVE that students can physically interact with works of art and get a deeper understanding of material we are studying.