Since my studio is a 10 by 12 room with one window on the west side of the room I often think about what is the ideal studio. I would like to have a room with lots of storage, large windows for natural light, a small kitchen area plus an area to sit and look at art books or to look at art in progress from a distance. Right now I take my paintings outside in order to see them better. Not when it's raining though.
I have bookmarked several studios I like. The neatness or messiness doesn't matter nor does the sort of art created in the studio. Artists just know what looks like a good studio to work in.
Here is a place to start looking at artist's studios.
The images above are just samples from two studios on the site.