People often refer to anyone in this profession as an "Interior Decorator." I used to correct people, but that got old. I found this article today, and liked what it had to say.
"The first thing to know before you set out to find the right interior designer is the difference between an interior designer and an interior decorator. Interior decorators are educated in the art of working with most any existing interior space and they know how to accommodate the client's taste to develop a coordinated overall look. Home interior decorators don't generally address safety or structural issues, functionality or efficiency; however interior designers are expected to consider these issues.
An interior designer is a degreed professional capable of designing efficient environments by considering all the elements relevant to the room's purpose. The right interior designer knows how to coordinate the available space by considering traffic and work flow, furnishings, fixtures, surfaces, and lighting. The right interior designer knows how to work with architects and has a network of qualified craftsman at his or her disposal." -Interiordesignersonline.com
It's an amazing experience to have the experience of telling where to put walls, and such, and then see that picture that's in my head, actually come to fruition!