Mine is a basement garage space. Gun work is constantly competing with everything else that needs fixing--a lawnmower is sitting upside down in the middle of the floor right now. Dedicated space is my dream.
A couple of guys here have mentioned having more than one bench. Having two benches has really helped me deal with tendonitis, bad eyesight, and back pain.
I have one low bench that is very heavy, but movable. It has splayed legs, so that it won't tip. The top is a 2' x 3 1/2' rectangle. I have one heavy machinist vise mounted on one corner. On the other end I have a movable block (with a slab of thick leather glued to its top) that I clamp down with screw clamps. I can move it to accomodate what I'm working on. This gives me a good height for heavy work, like inletting a barrel. The height of this table is determined by the height of the vise, and I set it at 38 inches to the top of vise jaws. (This is a good height for me. I'm 6 ft.)
I have another bench, a long one, bolted to the wall and set under a window for light. I have small vises bolted to each corner, and set so that the height to the top of the jaws is 47 inches. This works well for me to do light, detail work, without having to bend over to see it. Having a vise on either end allows me to clamp the forestock or buttstock as necessary in either the right or left end vise as needed, put the work area under the window. But note that this tall bench would not work at all for heavy work, as it absolutaly kills my elbows to do any heavy work at that height. And I could never do the detail work at the low bench, without killing my back.
I'm describing all this here on a string about shop size for the simple reason that if my shop, small as it is, wasn't big enough to accomodate both benches, I would proably not be able to work on guns. Having both of these allows me to avoid over-stressing my elbow and back.