I'm surprised this morning that there's even a debate about open plan living. I can't imagine anyone wanting a kitchen and living and dining area separate, and ideally also spilling out into some sort of outdoor entertaining area. Sure a separate formal lounge can be lovely, as can a separate entertainment room, and you absolutely need privacy in bedrooms and bathrooms, but open plan living areas are fantastic for having lots of light and a communal space that people can enjoy together. As long as its not too big then heating/cooling and noise isn't really a problem is it?
Who doesn't like open plan houses?