I've been thinking about this too. (And also thinking that the architecture-focused areas of SecondLife might be a good way to explore this). Also, I used to know how to use Blender; even played with the Python in it once.

But what do you need all those rooms for? Why do people have a separate dining room, living room and family room?

A gym, I can understand.

A bedroom I can also understand.

But lets start with bathrooms. The bathroom should be designed so that you can hose it down. There should be no wood or particle board, or even drywall. Buckminster Fuller's Dynamaxion house bathroom is too small. There should be a soft plastic king-sized bed under the showers, so that you can relax horizontally under the streams of water. There should be one of those Jacuzzi hot tubs with a water proof monitor and a floating keyboard, so that you can catch up on your blogs while relaxing your muscles and ridding yourself of lactic acid. Also, perhaps a UV germicidal light and an ozone shock generator could sterilize your bathroom while you are out of it. Don't forget the full-body scanner.

Dining rooms next. Dining room chairs are way too uncomfortable. Plus, these days, a lot of conversation revolves around things that are on the internet. So a perfect dining room would be a few La-Z-Boy recliners with tray tables and over hanging monitors (from this place: http://easychairworkstation.com). Perhaps there could be one central projector that could alternately display images from each person's personal screen, when it was their turn to talk.

What about kitchens? I like science, and I never learned enough chemistry to satisfy me. Kitchens should be designed according to the philosophy at this place (http://khymos.org/tools.php), as a scientific laboratory. Recipies should be done in LabView, and all kitchen machinery should be servo-controlled.

Living rooms are next. What are they used for? People gathering and talking, mostly. What do they talk about? Things on the internet (or things that could be researched on the internet, instead of talking out of your ass, about things you know nothing about). Again, a setup with La-Z-Boy recliners, with overhanging screens, and a projector that can display individual screens onto a wall when it's your turn to talk. If you're foolish enough to play video games, a setup like this could also accomodate you.

So living rooms and dining rooms would be indistinguishable from each other.

What about interior decorations? Meaningless art from Wal-Mart on the walls might as well be holes in the wall. Maybe Escher could be a good start. Posters with geometrical proofs of the Pythagorean theorem would be nice. Particle accelerator bubble chamber photos would be nice. Timelines of world history would be cool (http://www.worldhistory-poster.com/en). Photos of nebulas would be great (http://www.spaceimages.com/index.html). Tons of stuff purchased at Maker Fairs (http://www.makezine.com/02/makerfair/)

Maybe an astronomical observatory would be cool (http://www.nytimes.com/2007/10/04/garden/04observatories.html?_r=1&ex=1192161600&en=5eff0c6f8c36b293&ei=5070&emc=eta1&oref=slogin) but I hate the feeling of all of my desires and passions being squeezed down into a tiny little eyepiece on a telescope.

Interior vertical gardens (http://images.google.com/images?q=vertical+garden&ie=UTF-8&oe=utf-8&client=firefox-a&rls=org.mozilla:en-US:official&um=1&sa=N&tab=wi) and hydroponics setups would be neat (http://images.google.com/images?svnum=10&um=1&hl=en&safe=off&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&q=kitchen+hydroponics&btnG=Search+Images). Even aquaponics setups winding their way through the house would be fun (http://www.bloggingwv.com/the-worlds-most-amazing-fishtank/).

Exterior appearance should be something like this: http://www.plan59.com/av/av357.htm or this: http://www.plan59.com/av/av404.htm

Finally location would be important. Perhaps this would be a good guide: http://www.survivalrealty.com/