The long term (think 'resale') effect of the choices you make in creating a custom home now will result in either gains or losses in the future. What does that mean?
The choice of house style/layout and materials/finishes on a particular property sets the value of the home now and down the line.
Make sure you think a few years forward as you select between 'modern' and 'traditional' and all the iterations in-between. For some people it doesn't matter, it would seem. But the potential for loss can sting.
What about an emergency sale due to unexpected economic or health changes? Can you recover what you have put into your custom home?
Certain areas of the country have regional styles based on the history of the area and zoning laws which can govern heights and materials. Going with the regional architecture is a 'safe bet'. Bucking the tradition is a risk and gamble. But low maximum heights mean either a single story traditional design with a low pitched roof or a two story contemporary -- necessitating a flat or slightly pitched roof. Of course the two stories yield more living space and on an expensive lot, this may be the only logical choice.
Trendy houses are being built everywhere now. There are contemporary revivals, transitional designs, mid-century moderns, anything goes, and traditional/regional design. Does a current fad or trend hold up in terms of resale? What style has been perfected and has less problems with weather, material failure, energy savings, etc.?
Only one of these approaches is based on a 2,500-year pedigree that is recognizable, tested, and beloved. Well-crafted Traditional design is a verifiable appreciating asset. More people will feel safer purchasing a classical or regional design over a contemporary one. The value holds up better over time.
The flavor of the day may go out of fashion depending on social and economic factors. The fact is that flat roofs, expansive exposed glass, and scaleless form are more expensive to heat/cool, maintain, and often have a soulless character. Of course, for most of the architects in practice today, "Modern" was the ONLY manner or style of architecture taught and believed relevant for a contemporary culture. It was a mandate over which one could be cancelled in fact!
I fully expected, yes EXPECTED without question -- after graduation from Texas A&M, that all my clients would demand contemporary or modern designs. But where I started out, in Austin Texas, traditional forms were the mainstay. This is true in the most high end neighborhoods in Dallas, Houston, and San Antonio. In Florida now, the regional Mediterranean style prevails but hotspots on the coasts boast Modern designs that, due to the particular areas, may hold value as demand right now is strong.
As far as interiors... my suggestion is to integrate the exterior design of the house with the interior design. Of course many historic houses can be gutted and made totally modern inside, but that is an exception. Why shock your guests (and your own psyche) with a change up when you walk through the front door? A traditional house need not be stuffy either. Contemporarys have certain furniture and accessories that must be used to stay 'in the mood'. Traditional interiors do not have to be overly ornate with moldings and millwork. There are countless ways to meet the zeitgeist in either case.
What is the perceived value of a house? Curb appeal (style, materials, landscaping, lighting) is the first value judgment made. Flow of space, views, quality of interior materials/plumbing/electrical/cabinetry, colors, light, furnishings and accessories, all work together to complete the value judgment.
THE CONSENSUS PLEASE
I have been designing mostly traditional houses for over 35 years. I was going to build a contemporary design for myself in Austin several years ago and at the last moment converted it to a French style! There is a time and place for everything.
In ARs collective wisdom and experience: Which style increases in value best over time?
My feeling is that only timeless beauty and lasting quality are the foundations for luxury homes in most markets.