It's interesting to read about the way other people use the program. For me, these features are the most commonly used

Superfly Morph Brush Copy Joint Zones script (because I use a WM V4 figure in most of my renders) Cloth Room Python Scripts, especially EZ Skin 3 and VWD, which I'm now almost always using for conforming clothes Material Room Graph Window (helpful for getting figures into the right position so that VWD and the Cloth Room work properly) Animation

Pretty straightforward, I'd say. The Hair, Fitting, Face and Setup Rooms are essentially useless to me. I never use them.