I think that a nice big sink is essential in a laundry room.

A sink, a place to fold clothes and do prespotting, etc. and a place to store the detergents and other stuff out of the way so they don't sit on top of the machines. If you don't want to build things you might try Ikea. They have many great, mostly inexpensive storage ideas for small spaces.

I am envious of your laundry room. My W/D is stacked in the kitchen and I fold my clothes in the living room. Not fancy, but it works.

A place to hang clothes.

The ability to easily install the machines in either arrangement, washer on the left or washer on the right. This in case you ever want to buy a right-hinged washer like Miele.

A place to iron clothes, if u iron. I dont mind ironing, I just hate dragging out the board

A drain in the floor, lower than the walls in case of leaks/floods

Do people hang dry clothes in America? I don't anyone who does, besides myself. Whereas in Australia, the hills hoist in the backyard is a common and endearing fixture in the Aussie landscape.

Vansky - Yes I use a "passive solar powered clothes drying apparatus" also known as a "clothes line".

I hang clothes to dry as well. I had a dryer, but donated it because I don't use it. In inclement weather, I have a huge greenhouse I hang them in because I don't grow crops in that house in winter. LOL.

Laundry Rooms are quite often multi-purpose rooms. Is yours slated for more than one purpose?

For Laundry: A sink, a retractable drying rack, a fold out ironing board, a folding area, ample storage for all the laundry essentials, a large area for soiled laundry, a place to hang clothes, a place for coats jackets, boots.

Is this also a mud room? A chair or bench and a place to clean boots and shoes. An easy sweep out threshold. Durable floor surface for wet and dirt.

Do you have pets? Will they be sharing this space? If so, you may want to make sure that there is plenty of room for pet food and water and a place to kennel a pet.

Make sure the room is drained properly so that accidental flooding does not damage the rest of the house. Windows with lots of light, natural light does wonders for examining laundry and for your attitude.

Hook-ups and drain centrally located so that various installations are possible. Using stackable appliances? make sure that the clearance above is adequate.

Don't skimp on an exhaust fans and venting, make sure that the air can be exchanged in the laundry room so that excessive heat or moisture can be vented.

Add power outlets above counter height for irons, radio, etc.

In my previous house I created a large laundry room with plenty of counters for folding, lots of square footage for baskets and hampers and an ironing board, and wall cabinetry for storage. It was a dream! And it was always a mess! It was too convenient for people to dump clean stuff on the counters, sort dirty stuff on the floor, and in general leave clothing everywhere except the pretty hampers.

Now my W/D are in a closet in the upstairs hall. It is clean and neat because my family is forced to sort and fold their piles in their own rooms. :)

Thank you, everyone, for your very helpful comments. You gave me several ideas I hadn't thought of. I wasn't sure about including a sink, but now think I will try. And a drain. I'm not sure whether the space will also lend itself to mud room usage, will have to see once I get a clearer idea of the overall dimensions. Any further ideas--or pictures--will also be appreciated.