Amy and Jonathan Kales kept looking at each other, sometimes with a smile, other times with an encouraging nod or a worried glance. They had been in the showroom for almost two hours at this point, on a buying spree, picking out all the extras, the "upgrades," that would turn their new Fair Oaks town house into their dream house.

Samples of their design choices--new carpeting, flooring, kitchen cabinets, etc.--lay splayed on the floor near where they sat with design consultant Barbara Hoskins.

"Is this an area of conflict?" Jonathan Kales, 30, asked his wife. The topic: a ceiling fan and whether they wanted one in the nursery-to-be. It was just one of a dozen details they had to decide on. "I can't remember anymore," he added.

At one point in their visit, Amy Kales, 27, declared, "This is fun," smiling hopefully at her husband.

Finally, though, they were done. After three visits to the Centex Home Selection Center in Chantilly, the couple had mulled over, discarded, agreed upon and bought all the upgrades they wanted for their new Centex town house, the first home they've purchased.

Upgrades are any items above and beyond what's included in the base price of a new house, from crown molding to more expensive kitchen cabinets to ceramic tile instead of vinyl flooring--and they cost money. By the end of this session the Kaleses had spent $18,000 putting their stamp on their new town house, bringing its total cost to $282,030.

Here, then, is the world of new-home buying today, where buyers no longer just pick through two-inch-square carpet samples in the artificially lit basement of a model home.

Instead, half a dozen Washington area builders have opened plush showrooms where they display full kitchens--the better for buyers to see what a wall of maple cabinets will look like, the better for them to be tempted by the matching refrigerator with maple panels--and an ever-increasing array of upgrades that buyers can add to their new homes.

In these showrooms, typically called design or home selection centers, builders sell anything from appliances to curtains in an effort to become a one-stop shopping center for their clients.

"This is where your new house becomes your new home," said Charlie McAuliffe, a design consultant at the Ryland HomeStore in Fairfax. "It's customized to your taste. This is the fun part."

"A lot of companies like ours have opened design centers," said Patrick Annessa, executive vice president of Denver-based Richmond American Homes, which opened its center in Fairfax in March. "We jumped on the bandwagon."

Annessa estimated that sales of upgrades in this area have increased 30 percent to 50 percent since the center opened.

Beazer Homes USA Inc. is the latest builder to adopt the design center concept in this area, opening a 1,300-square-foot upgrades showroom in Tysons Corner just two months ago. Beazer, a national builder based in Atlanta, already had centers in several other locations around the country.

"The No. 1 reason we did it," Beazer President Don Knutson said, "is to improve customer satisfaction. It's a showroom type of setup. We can display more options, and it's not rushed for the customer like it could be in the model home."

It hasn't been like this for long. Ryland design consultant McAuliffe said that just a few years ago, options were much more limited, and buyers were kind of on their own.

"The person selling them their home would also sell them the upgrades, and they weren't design specialists," McAuliffe said. "This way the customer gets individual and more expert attention."

McAuliffe acknowledges that Ryland's design center is also about profit. "Since the design center came into being, we've definitely sold more upgrades," he said. The National Association of Home Builders estimates builders usually have a profit margin of 9 percent on a new house.

Following a common practice with design centers, Ryland put its HomeStore close to its division offices. That helps with paper flow between the design center and the builder's main offices and is useful for answering questions clients may have.

Builders with showrooms require that every buyer visit the home selection center after their purchase to see the builder's standard faucets and floor tile and decorative hardware--and to look over the upgrades available. The builder will usually schedule two separate two-hour appointments for clients with design consultants, who show them the many options available and offer guidance on anything from floors to lighting.

Many of the centers discourage walk-in customers. Said McAuliffe, "If people are walking in and asking questions during [someone's appointment], I can't give anyone my undivided attention."

Because of design centers, builders say, customer design errors have gone down.

"It's hard for buyers to imagine what these upgrades will look like in their homes, so the bigger the sample, the better," said Hoskins, who manages the Chantilly center for Centex Corp., a national builder based in Dallas.

Managers at the local design centers wished they had more space to showcase entire rooms. They all agreed that the more you can show, the more comfortable clients are with buying--and the more they spend.

Upgrades have been selling well at all the design centers, the longest-running of which has been open only a few years, largely because of the country's brisk economy, managers said.

"People have deep pockets now," Hoskins said. "They want ceramic tile and hardwood floors. Builders can make money selling these things. Why let the furniture store down the street get the business?"

Centex even tried selling furniture at its selection center for a couple of years, Hoskins said, but decided to give it up. "It was hard to learn everything about furniture and be completely knowledgeable about it."

The Centex Home Selection Center, unlike some of the other design centers, sells lighting fixtures and window treatments, all of which can be rolled into the buyer's mortgage. Using the design center, a buyer can almost completely furnish his house--everything except the furniture itself--and pay for it all in the monthly mortgage payment.

Still, there are limits. The builders typically don't sell every line that a cabinetmaker, for example, will offer. When Centex moves up to building more half-million-dollar homes, Hoskins said, the company also will offer semi-custom lines. At the moment, for example, only the cabinetmaker's "production" line of cabinets is available as an upgrade. But even those basic lines can provide daunting choices.

Most of the builders who have opened design centers in the Washington area cater to either first-time buyers or first move-up buyers. The luxury-home builders haven't jumped on the design-center bandwagon yet, still mulling over whether it's right for them and their customers.

"Our buyers are typically buying their third and fourth home from us," said Kira McCarron, vice president of marketing for Toll Brothers Inc., a luxury home builder based in Huntingdon Valley, Pa. "Typically, both adults are working. They don't necessarily want to drive to an off-site center." Toll Brothers instead opens small temporary centers at the communities it is building.

McCarron said Toll Brothers wasn't sure the design center concept would be "a perfect fit" for its clientele.

"It's a more mass-merchandising approach," she said. "Our homes are almost custom homes already."

Design center managers say customers can spend tens of thousands of dollars on upgrades. Hoskins from Centex said the center's biggest sale to one customer amounted to more than $50,000, almost a third of the price of the house he bought.

Builders with design centers often have promotions on upgrades in an effort to start customers buying. Centex, for example, is offering a $2,000 gift certificate at its selection center if a customer buys a condominium, town house or single-family house between now and Jan. 1.

But no matter how the builders display it, how many options they present or how many special offers they promote, there always are some people who just don't want to spend any more money than necessary on a new house.

"We've decided to go with no upgrades," said Ishmael Intsiful, who was looking around with his wife, Marta, at the Richmond American design center in Fairfax last week. "The standard features are fine.

"I took off work to come here," said Intsiful, a management consultant in Bowie. "I was afraid that if I let my wife come here alone, she'd pick everything they have. With me here, that just won't happen. I watch the bottom line closely."

Home Builders Can Attest: Custom Doesn't Mean Unique

Home builders who have central design centers offering optional cabinets, carpeting and other custom touches report a lot of the same items selling briskly. Those choices add up to a better snapshot--of what's really hot in home fashion and what people are willing to stretch the budget for--than any decorating or tech gadget magazine.

* Because many entry-level houses feature basic carpeted and vinyl floors over subflooring, hardwood floors are an option that home buyers have to pay for. And they're a big seller, the home builder design centers reported, not just for living and dining rooms, but also for kitchens.

* Buyers are going for lighter-colored hardwood floors, a honey-colored floor rather than the darker shades that were more popular a few years ago, design center managers said.

* Berber is today's carpeting of choice in family and rec rooms because of its durability and casual look. Favored colors are neutrals such as beige.

* For kitchen cabinets, "dark" is almost completely out, and a light, natural maple is the preferred choice, with white still a close second.

* For kitchen counter tops, those who can afford it are opting for Corian solid surfaces with seamless Corian sinks in a neutral beige. Very few design centers offer expensive granite counter tops. The best-selling Formica or other laminate counter tops are in neutral tones.

* Another option selling well at all design centers is wiring packages that allow for telephones, computers, fax machines and television cable lines in one wiring package.

-- Daniela Deane