Use to a lot of space? Then the new space needs to feel big, even if it isn't. An open floor plan really is a help in that department. However, that open space can have defined areas. The dining room may really be a part of the living area, yet set apart.
As you can see from this view, this home is open from the foyer, through the Living room and dining areas, and if you look closely to the right, you will see it is open into the Kitchen area.
This house feels huge, yet the amount of space is a mere fraction of the old place, and isn't it lovely?