When visitors to New York, or even some residents, are asked about landmark, historic or architecturally striking buildings here, they'll probably mention the Empire State Building, the Chrysler Building, the Woolworth Tower, Grand Central Station, the Guggenheim Museum, the Flatiron Building, and maybe the Museums of Modern Art and Natural History and the United Nations.

Ask them about significant or landmark apartment buildings, however, and most will have to think twice. Most will know the Dakota - but probably more for the fact that John Lennon lived there than for anything else.

The city is full of architecturally significant residential buildings however, many of which are now co-ops and condos. Their history is much less celebrated than their commercial counterparts, but these buildings are innovative nonetheless. Furthermore, architecturally innovative apartment houses are still being built in New York.

Center of Innovation?

Is New York City a center of architectural innovation and experimentation? Opinions among architectural professionals vary.

Architect Daniel Koplowitz of Preservation Design Group in Blauvelt, N.Y., which is in Rockland County, says, "New York is the center of the universe. It has some great schools, like Columbia, and you get the cream of the crop in all aspects of design, including industrial and architectural."

Darius Toraby of Darius Toraby Architects in Manhattan says, "It's the largest metropolis of the world, and you have professionals from all over the world doing work on buildings in this town. All the largest corporations and the most famous families have real estate interests here."

However, Laurie Maurer of architectural firm Maurer and Maurer in Brooklyn says, "There are a few star buildings in New York, but the overall development of design in New York is really very low compared to other parts of the country and other parts of the world. Chicago is the architects' city, but we're not anywhere near that - the typical developer is not interested in doing anything more interesting if it means it'll cost a little more."

Deborah Gans of the firm Gans & Jelacic, who teaches at Pratt Institute, believes that while the city has recently begun to be a center for architectural innovation, with standout new buildings by Renzo Piano - who designed the new New York Times building - and Norman Foster - who designed the new Hearst Tower, "It was not so for 10 or 15 years. We lagged behind Europe."

Some Star Buildings

One thing nobody will disagree on is that some apartment buildings definitely stand out. Here are some that the five architects and one architectural historian interviewed for this article mentioned:

The four, 1970s-era Waterside Plaza towers in Murray Hill.

• The circa-1930 San Remo and the circa-1931 El Dorado, both on Central Park West and both designed by Emery Roth.

• The Astor Place Tower, a mixed residential condo/retail development, completed just last year and designed by Gwathmey Siegel and Associates.

• The ornate, circa-1908 Alwyn Court at 58th Street and Seventh Avenue, which architect Howard Zimmerman calls "the greatest terra-cotta mecca in New York."

• The early 1930s, multi-building London Terrace in West Chelsea.

• The Ansonia on Broadway between 73rd and 74th Street, a former hotel with turn-of-the-century charm that was almost destroyed in the '70s.

• The early-1960s Kip's Bay Plaza, notable for its concrete-grid exterior and floor-to-ceiling windows,

• Architect Richard Meier's recent, high-profile residential towers in the West Village, overlooking the Hudson.

• Costas Kondylis' buildings, such as the soaring Trump World Tower near the United Nations, and his Chelsea Centro (both 2001), on West 26th Street.

• The aforementioned Dakota at One West 72nd Street, opened in 1884 when much of the Upper West Side was still farmland.

• The Apthorp, occupying a full block between 78th and 79th Streets, Broadway and West End Avenue, and completed in 1908, notable for its ornate gate and inner courtyard.

Brownstones in general, "an incredibly important building type," according to Brooklyn architect Wids Delacour.

Of course, there is bound to be disagreement within the architectural community. For example, one architect interviewed for this piece calls the Astor Place Tower "Just a look-at-me building, really ugly - only a show-stopper."

Changing Trends

In designing residential buildings, much has changed since the days of the Apthorp and the San Remo. Some of the changes are apparent - more use of glass and steel in the façade, for example. Building codes have changed, including light and air ratios and safety standards - you won't see asbestos used anymore, for example.

In an increasing number of buildings, energy-efficiency - a concept that hardly existed before the 1970s - is a major consideration. Also, apartment buildings tend to be taller and thinner, since developers and architects don't have the large amounts of land they used to have to work with.

"Back in the 1950s and '60s, you had some apartment houses that took up an entire block," says Zimmerman. "You don't have these huge sizes any more. Many buildings are half the size the used to be, with fewer apartments on each floor."

The real-estate market, and the trend toward more and more luxury condos, also affects design. The apartment building market today, says Gans, is divided into luxury on one hand, and very modest - often government subsidized - housing on the other. "You don't have the variety of units that you used to," she says, although she is heartened by the fact that rental buildings are on the rebound.

Inside the buildings, larger spaces, including kitchens, bathrooms and closets, are more in demand. Henrik Krogius, photographer, architectural historian and author of New York, You're a Wonderful Town, Arcade Publishing, 2003, remembers, "In the 1950s, after World War II, the main thing was to give people a volume of apartments. They had to meet a large demand for apartments, but were building them on the cheap with low ceilings and very small rooms." Later on, many people became more affluent and wanted more space.

One of New York's most important residential contributions, Toraby says, has been the idea of loft renovation, which began in Soho. "The use of old industrial buildings and school buildings [for housing] and the gentrification of old dilapidated neighborhoods primarily began on a large scale in New York City."

Get It Done Yesterday

Not only did changing fashions and demands, challenge residential architecture, but the circumstances of the city itself and its astronomical land values played a major role.

We've already mentioned the scarcity of land, spurring taller buildings. Add to that what Koplowitz terms the "congestion" of the city bureaucracy, dealing with union issues, and finding good contractors.

There's also the proverbial hurriedness of New Yorkers themselves. "Everyone wants it done yesterday," says Zimmerman. "Get it done, get it built, get it occupied. Everyone's under pressure to produce."

Delacour finds that the city's zoning laws make it difficult for architects to design low-rise, high-density buildings, because they mandate a 50-foot space between the rear wall of one building and that of the next one. Without this rule, he says, architects "could create a little more density and have interesting designs, if it's all done well." Still, he says, "zoning works fine with high-rises."

Exterior and Interior

With all the changes and demands, the basics of good residential architecture still stand. Several of the architects interviewed for this article pointed out that a creative exterior design and an interior layout, with a good use of space and light, are both very important. Maurer says she likes to work from the inside out, "To accommodate an intelligent use of design that generates a plan, and the plan generates the exterior."

In addition, attractive lobbies and amenities such as built-in health clubs are important to buyers nowadays, and are part of the overall design.

Delacour says that his firm, Delacour & Ferrara, strives "to create a community or neighborhood, and if you're doing both sides of the street, you can do that, to create a street people want to live on." As an example, he cites Columbia Terrace in Brooklyn, where in the 1980s, he helped create several blocks of three-story affordable buildings similar to brownstones.

Residential architecture, like everything else, also must respond to economics. "In construction, methodology is cost-controlled by maximizing the zoning and floor-air ratio by use of air rights," says Toraby.

When all is said and done, architecture is only one of the draws of a building - you can't forget location. "A building on Fifth Avenue has more cachet than one in Williamsburg," says Koplowitz.

Don't Forget the Engineer

Creative architects are celebrated in the pages of prestigious periodicals, but they're not the only ones responsible for the design of the building. You also have the engineers to thank for a good building.

The relationship between architects and engineers is complex, and those interviewed for this article had varied opinions about how the two professions work together. Some insist, basically, that the engineer works for the architect and should defer to him or her. Others think of the relationship as working more hand- in-hand.

"The architect is usually moderately trained in certain areas of building structure - such as mechanical systems for example," says Maurer. "But he still does not have the depth of training of an engineer. You use the engineer as a consultant. He should be able to work with you, and the architect has to be conversant enough to work intelligently with him."

Residential building projects sometimes will have several engineers and several architects - both an exterior architect and an interior architect for example, or both a mechanical and a structural engineer.

"The architect is concerned about whether the building will look nice, and whether the layout of the rooms will be good," says Krogius. "The engineer is concerned with whether the building will stand up, whether the water will run through the pipes, and how the electricity will be provided."

Coping with Coping

Co-op and condo board members, shareholders and managers will at times interact with architects - especially at meetings to discuss renovations or additions. Often, architects complain, laymen have a hard time understanding what they consider simple concepts.

Among the terms that some of the architects feel board members and managers should understand are:

• Parapet:a low wall along the edge of a roof or balcony

• Bulkhead:a small enclosure on the roof for a water tower, stairway or elevator

• Cornice: a horizontal, molded, often decorative projection that protrudes from the top of a building's exterior wall, found often in older buildings

• Coping:the capstone on top of a masonry wall.

• Torchdown:roofing membrane applied with a torch

• The difference between a beam (which is horizontal) and a column (which is vertical)

• Waterproofing:the protective treatment of a surface to prevent water from penetrating or escaping specific areas and causing damage

• Reglet:a narrow, flat architectural molding

"A co-op or condo should get people on the board who are familiar with construction, with every single term that comes up," says Delacour. "They should hire a building manager who knows this stuff."

It's not only technical terms that building managers and boards should know - it's certain concepts as well. One of these, Maurer believes, is that even if a building is well-designed, it must be well-maintained. She has seen cases where, years after the building is constructed, "A [building's management] comes after the architect [with a lawsuit] for a so-called design flaw. Time after time, it turns out to be a maintenance flaw."

Whether you live in a strictly utilitarian steel-and-glass high-rise, or a richly ornamented terracotta treasure, your home is the product of collaboration between both architects and engineers, and weds age-old architectural techniques with modern technological advancements. With communication between professionals and conscientious maintenance by board and management, your building will stand strong for generations to come.