Welcome from Wisconsin! Sounds like you have the start of a wonderful sewing space.
My space is a spare bedroom with a large window. I would ditto the shelves for fabric. I have a metal industrial-looking unit that I bought at Target. That's where I store my plastic covered totes of fabric. They're labelled "batik", "civil war", "30's", "christmas", etc. as well as blue, red, green, white, etc. It works well to pull the totes out, pick fabric and put them back without much bending. Of course there are larger plastic boxes on the bottom for wide backing fabric, flannel, and fabric that I have a lot of like "brown" and solids. I also have an armoire where I put my unfinished projects, stabilizer, freezer paper, embroidery floss, etc. then I have another small wooden shelf with those old glass candy jars. Those are where I store my threads. There are so many things you can do to make a fun, organized space. Of course, don't forget to save a nice space for a design board (mine is just a piece of Warm and Natural thumbtacked into the drywall).
Happy quilting!