One of the most annoying things about our current layout is that to get from the bedroom level to the basement, you have to go down a flight of stairs, through the living room, through the dining room (around the table), through the kitchen and then down to the basement. In order to fix this, we are opening a doorway from the kitchen to the living room. See the red circle between the rooms - that's a new doorway!
In order to create more kitchen space, we closed off the doorway to the outside (in the kitchen) and the doorway to the bathroom - both are circled in blue. We have a side door to the outside off the stairs by the kitchen and another door to the backyard from the office. We didn't really need a third door! We also didn't really want the bathroom opening off the kitchen and it gave us a great place to put the refrigerator - right by the breakfast nook and the dining room so the kids could get drinks and snacks without going near food cooking.
Since we closed off the bathroom door, we opened a new one off the office. Much better place for a bathroom IMO!
Other items not shown: we added 3 transom windows between the dining room and the office, plus 3 skylights in the office. Our dining room is painted a dark green and sucks the lights out of everything (we are painting it a light blue to help with that). It has one set of windows to the outside, but those are blocked by a lovely tree so natural light doesn't flood in. There was also a window to the office that we closed off to make the office a bit more private. The transom windows allow light from the skylights to enter the dining room, giving it a much better natural light source.
So to sum up: RED = added doorway, BLUE = closed up doorway
Oh and in this drawing (its old), PLAYROOM is what I call the OFFICE.