Yeah, I would have killed for a place the size of yours in Yokohama... we were in a 14x7 foot shoebox with a loft (which should have been where the bed was, but the bed frame didn't fit up there, so it turned into luggage storage).
Having said that, when I eventually buy a place, I'm not looking for much space... just enough for everyone in the family to have a bedroom and a little private area to work in. I think huge houses are a stupid waste of space, even in a country like Canada.