My studio space has been a constant work in progress since I first moved in, and I think it's finally evolved into something in which I feel comfortable. One of the most recent additions is a new industrial table for sewing to match the one I use for pattern drafting. The added table space has already made a huge difference in productivity. Also I made a bulletin board by covering a piece of homasote with linen so that I can always have my inspiration and calendar within eyesight. (The calendar really helps me plan my schedule because juggling tasks and keeping track of deadlines can be so difficult.)
Other than that all of the changes have been purely cosmetic. Like my home, I prefer my workspace to be cozy, which to me means color and pattern. I painted one of my walls a pale greenish/grayish blue (this color to be exact), and I love it. It goes with the antique rug that I got on eBay from this store. See more of my studio here.