My sewing room is an odd shaped room. I think it is 9 x9 but it is L shaped so its just strictly for me to sew in. That being said I also have "visitation rights" to the longarm at my parents. That room is 25 ft x the width of the whole house (110ish). The table for that is 18ft, so once you have the room on the ends for you to walk around you need the extra few feet.
The longarm at one end, the embroidery machine & serger on the other end & a Martelli cutting table in the middle.