On the outside, it's likely to look like a traditional two-story home. But on the inside, it may be a collection of cathedral ceilings, angled walls and arched windows.

In the era of rising land costs, architects and builders throughout the Washington area are constructing more homes per acre, but they also are realizing that they have to give buyers a bit more in less space. And they apparently understand that cookie-cutter subdivisions must not only have affordable prices, but lots of character and a personal touch to attract a wealthier and more selective home buyer.

"The Washington market ain't what it used to be," William J. Devereaux Jr., a division manager with Berkus Group Architects, told builders and architects at last week's annual Washington area building trade show. "It's more sophisticated than it was 10 years ago. Buyers are looking for the formal, sophisticated look. People want the feeling of larger space. They don't want to feel locked into smaller rooms."

Nowadays, architects and builders say they are reaching for young urban professionals, double-income and childless couples, and couples whose children have grown up and left home. While there still is a healthy flow of first-time buyers, there also is a growing number of existing homeowners looking for move-up houses with more flair and amenities.

With the promise of increasing population and rising incomes here, architects said they are designing homes for people who have "BMW and Mercedes-Benz" tastes. "They're willing to use columns or marble," Devereaux said.

Unlike 15 years ago, when architects and builders wooed home buyers by using light-colored woods, they now are designing homes with larger windows that create more openness and brightness. They believe buyers want a simple, sophisticated look -- and are willing to pay for it.

When buyers walk into a new home these days, they may find an open room with nine-foot-high ceilings and arched windows near the top of the walls to shed more light. Inside, there might be rounded or squared columns to create more airiness, and separate rooms without confining walls.

Buyers also might be able to customize their fireplaces, perhaps by using decorative ceramic tile or installing a two-sided fireplace with one side facing a family room and the other a bedroom.

Architects say kitchens are expected to be a bit roomier and designed more as family meeting places. Islands, usually accented by a butcher-block top and a hanging pot rack, will become common in larger homes. More homes will be designed so that the kitchens, family rooms and breakfast areas adjoin.

Islands "are becoming one of the most important elements in the kitchen," Devereaux said. "Houses used to be designed so that the kitchen was in the back of the house and the wife stayed home and looked out into the back yard as she worked. But households are no longer like that. ... Two people, who may not see much of each other, can work together. If you only know how to cook two or three dishes real well, you can lay them out and show them off to friends."

Hot tubs and whirlpools will be almost standard features in most bathrooms for master bedrooms. High ceilings and French doors connecting the master bedroom to the bathroom will become increasingly popular.

Mark Humphreys, executive vice president of Womack-Humphreys Architects, emphasized that the contemporary floor plan is going to be essential in selling new homes. But aside from the interior design, Humphreys said he and other architects are going to have to plan subdivisions to give residents a greater sense of individuality. The common row-house layout of many town house developments will give way to an assortment of new designs, he said.

The challenge for the architect and builder is determining how to creatively use smaller lots with a higher density of houses. Humphreys described the use of 10 kinds of lots on which his company has designed single-family detached and attached homes, town houses and apartments. In each example, the lots were designed with 10 to 15 units per acre.

In several settings, the houses were planned so that each faced a different direction yet was attached to the next by a wall.

With three-story condominiums, Humphreys said some builders reported they had problems selling the second-story unit. The first-floor condominiums sold because they had the advantage of access and back yards. The third-story units sold because they had cathedral ceilings. To make the second-floor units more attractive, Humphreys' firm redesigned the building to allow a cathedral ceiling.