Do you have a style or a theme that you try to stick to in your home?

You could tuck a couple of shelves in there, attached to the wall, then put baskets on the shelves. You could put potatoes/onions in the baskets, or linens, or maybe all of your measuring cups/spoons or all of your spices.

Or, maybe hang a curtain across the space with a simple tension rod to conceal some shelving if you are going for a country look.

I am not positive I understand what you're asking, but if there's a space where a dishwasher would go, how about just adding the dishwasher - or - another thought would be how about a trash/recycling center?

We left an empty space under our counter, towards the eat-in end of our kitchen. Our plan is to put a rolling cart under there (cart still in design stages) that will have a butcher block top and shelves below. We'll probably keep things like cereal that we want to access easily on the cart's shelves and I imagine the cart will mostly stay in its parking spot. But when I need a bit more counter/prep space or want to add serving space in the adjacent dining room I can roll it out.

If the cost of the cart is too much, we'll put a couple of shelves in the space and store things in baskets as gardenwebber suggests above.