Well if it is a building/painting based use room your needs are simple.
Counter along one wall. 2-3 feet deep, mounted to wall with a means of support that permits no impedment to legs underneath it. 8+ feet of length is fine, more is better. Regardless of what it is made of, have it painted white, parts stand out nice this way. Get some glass at least 1/4 inch think for a work surface (I find it makes a nice perfectly flat and non stick surface that can be cleaned with a razor blade or similar sharp item.
I have an 8 foot long table like the above.
For painting, assemble a booth area with ventilation exhaust built into one of the sides, make it big enough to work in (likely 3 feet wide is plenty).
After that, you have all you need really. Might want to get a few spot lights, or a couple of flourescent tube lights for oodles of light source.
I guess any remaining wall can be used for display/storage. Make sure there is room for the bookcase that can handle all your literature.