When it comes to studio decor, you'll want to be sure you select something that fits with your company image. Stodgy furniture or old-fashioned designs won't work well in the graphic arts industry. You don't have to go too far out on a limb, but you'll want to be sure you are decorating with a fresh and contemporary style.
Clean lines are always a classic choice, and you can even punctuate space with colors from your company's logo to help reinforce branding. Try to create a waiting area that is pleasant and comfortable, and consider hanging some artwork there as well. Plants are another good choice; just make sure they are low maintenance and that your lighting conditions will work for the type of greenery you pick.
In the design field it can be a good idea to set aside some meeting space so that you have an area to sit with clients and talk. Be sure and include a computer with a nice display in the room in case you are going to look at designs or discuss revisions. This way you can keep your own work area more private and set it up however it works best for you.