When I was growing up our house had a combined laundry/sewing room. It was a construction mistake (the laundry room was built bigger than intended), but it worked out well. As long as the laundry room has good lighting and enough space, it can be a great arrangement. If you have a front loading washer, a countertop on top of the machines can be a nice work space for both quilting and laundry folding. The iron and ironing board are right there for both activities. Starch, synthrapol, etc. work for both.
Oh, for comfort's sake, check if there is a ventilation fan or air conditioning in the room - it might get too warm to sew if the dryer is running. This really depends where the room is situated in the house.
And, as Peckish says, it is also nice to be able to close the door on it!