David Dukes did not have to be enticed into the condominium market. Single (actually divorced and hopeful that he'll be married again before too long), a weary veteran of the Sisyphean struggle to maintain a detached home, looking for a big deduction to ease the burden of being in the 40 per cent tax bracket, Dukes is the sort of person for whom the condominium was invented.

Before he actually went shopping, Dukes, who lives in an apartment in Hillcrest Heights in Prince George's County, knew what he wanted.

First of all, he would buy in Virginia, so he could pay a lower state income tax ("I'm in the 40 per cent bracket," he said with as much rue as pride). He computed wht the would save more on state income tax by owning in Virginia rather than Maryland, even though he would have to pay a personal property tax in Virginia.

Dukes also had his mind made up on size: two bedrooms and two baths. He might compromise on bedrooms, sacrificing one for a den that could do double service. But with his children coming to visit him on weekends, plus guests, there would be no sacrificing the second bathroom.

He also wanted a dining room that was "well defined," not just a section of the living room arbitrarily designated.

For price, Dukes set a ceiling of $50,000, though if he found what he wanted at a few thousand dollars more, he would be flexible.

Dukes chose to go shopping in "Condo Canyon," the cluster of high-rises near the intersection of I-95 and Duke Street in Alexandria.

One of his stops was the Olympus, a bleached white building whose filed-tooth balconies resemble the Watergate's (the one in Washington's Foggy Bottom, not the one just down the block from Olympus).

After the condominium overbuilding bust of a couple of years ago, Olympus went into foreclosure. The sales people in the lobby are candid about this fact, and point to the advantages of a post-foreclosure sale; cheaper interest rates (8.5 per cent instead of 9.5 per cent on as little as 5 per cent down) and the reduced price of reserved indoor parking ($2,500 instead of $4,000).

Dukes himself is unfazed by Olympus previous financial problems. "I'm looking for value for the dollar," he says, "I'm not concerned about foreclosure."

After looking at some floor plans and listening to the sales spiel, Dukes showed some interest in the Fairfax model (two bedrooms and two baths), priced at $52,000. With a 5 per cent down payment $2,600, his monthly bill would be $607, which includes the $171 condominium fee.

"That seems like a lot," Dukes said, weighing, as he always does, the figures that lead to the bottom line (he is deputy assistant secretary for financial management at HEW). "But it's a fair price."

Dukes next stop was the nearby Watergate at Landmark, which does not look at all like its namesake in Foggy Bottom. Both are owned by the same Italian real estate company, Societa Generale Immobiliare.

At Watergate, the carefully executed effects is one of luxury and security. Even Dukes, the figures man, is impressed by the arry of amenities. "That's a beautiful pool," he says, after he is driven in a golf cart by sales agent Robert Best to the edge of Village Lake.

Before he takes the tour, Dukes carefully examines all the models in his size range. Because prices at Watergate are higher than at most condos in the canyon, he concentrated on the models with one bedroom and den.

In one of the two bathrooms, he noticed there if full vanity, "This is nice - very nice," he said. "The Olympus only had half a vanity."

Watergate's models are furnished to give a lived-in look. In the den, for example, there is a man's robe on the convertible sofa, slippers on the floor and a briefcase on a chair.

The model that Dukese seemed to settle on as a possibility is slightly smaller than the two-bedroom Fairfax at Olympus, but he is impressed. "The dining room is more clearly defined," he says. And generally the space in the Watergate model is more open and usable.

Having spent $2 million on amenities, Watergate at Landmark has a powerful draw on potential buyers. Best led Dukes on a grand tour - past the outdoor and indoor pools, the party room, the game room, the pool and billiards room, the TV room (equipped with a Sony superscreen), the golf practice room - that would have made them the mind reel.

Security is personified by a watchman who makes his rounds amid all this dolce vita with a nightstick lashed to his waist.

Back at the sales office, Best tallied the figures up for Dukes. The one-bedroom plus den model Duke liked costs $53,000. The maximum down payment is 10 per cent, which would mean a total monthly payment of $599.67, including $124.82 in condo fees.

There is no free parking, no negotiating on the price. "Nobody gets anything for nothing," salesman Best said.

Later, on the way to his car and more Saturday shopping, Dukes said, "He's right - you pay for what you get. There are various trade-offs. Some are subjective. Pricewise, I think this place is worth it, if you can afford it. Now I have to go back home and see if I can afford it."

In June, Betty and Vernon Schreiner will move into their new $98,000 detached house in Magna Group's Karric Forest, a small development of traditionals in Oakton.

They did not stumble onto Karric Forest. It was within the radius they drew from the Tysons Corner area, where Vernon Schreiner works.

While Karric Forest offered them many things they were looking for (a mixture of housing designs in the development, a two-thirds-acre corner lot backing up to parkland, large rooms), the Schreiners were also impressed by intangibles.

"The builder happened to be there one day and he asked us if there was any particular way we'd like to have the house situated," Betty Schreiner recalled. I was pleasantly surprised that anyone would bother to ask us that. Our first choice, we were told, wasn't plausible because it would involve cutting down more trees."

For about eight years, Larry and Sue Tanner have known what kind of house they wanted to buy: Ryland's roomy, two-story colonial with center hall and garage. Everywhere they had looked at the house, the price was too high. Then they found the house in the new Ryland subdivision in Burke Centre. It had a new name - the Hamilton - but the design was the same. The Tanners paid $79,790 base price for their house, but they think they made a good deal. Near Reston, Mrs. Tanner said, the same house was price in the high $80,000s. It was cheaper in Prince William County, but that location was "too far" for the Tanners.

Priscilla and Ronald Stultz's house hunting took them from South Arlington to Sugarland Run in Loudoun County. They looked at detached houses and town houses, new and old. in the end, they bought an eight-year-old patio house just up the hill and around the corner from their apartment in Reston.

"If you want to know the truth," Stultz said, "I don't think we found what we were looking for. I expect we weren't realistic in our objectives."

Their first price selling was $45,000. In a county where the median price of all housing is reaching - if it hasn't passed above - the $65,000 mark, they were forced to raise that ceiling to $50,000, then again, when they reached a decision, to $56,900.

There were cheaper alternatives but in each case, the Stultzes found powerful negatives. The 20-and 25-year-old ramblers they looked at in South Arlington were selling for $50,000 to $55,000, and most of them had what Ronald Stultz called "personality" - added touches such as workshops, decks and paneling.

But Stultz was worried that if he and his wife bought one of the houses, they wouldn't be able to afford the refurbishing costs.

Stultz has no illusion that he and his wife (they have two children, 7 and 2) will be in their second-hand patio house more than a few years. "We're going to move to a small town>" Stultz, a native of Winchester, Va., said "somewhere in the Shenandoah Valley." CAPTION: Picture 1, Condominiums such as these town houses at Watergate at Alexandria, currently under construction between Pitt and 2nd Streets, are among the choices in Northern Virginia. The Watergate project is designed with an 18th century village in mind; its 20th century prices range from $85,000 to $125,000.; Picture 2, Home shoppers look through the model town house of the year-old Wethersfield project in Reston. Prices range from $69,900 to the high $80,000s., By Harry Naltchayan - The Washington Post