Five years ago this month, Frank Gehry's Guggenheim Museum in Bilbao, Spain, opened to nearly universal acclaim.

But as successful undertakings are prone to do, Gehry's extraordinary building stimulated imitation -- too much so, say some critics. Something called "the Bilbao effect," they say, is a horrible sign of the times. Or a sign of horrible times.

Either way, I disagree. The Bilbao effect does indeed exist and, by and large, it does more good than harm.

Initially, astonishment and admiration greeted Gehry's architecture. Set by the riverside in an abandoned industrial district, the big building is like an apparitional ocean liner sheathed in thin, billowing sheets of titanium. The world had seen nothing like it, and the world -- the Western art world, that is -- liked what it saw.

So great was its success in luring cultural tourists to Bilbao -- a gritty town down on its luck -- that other cities soon were clamoring to acquire one of those. Architects who had long labored on the fringes, tinged with the ambivalent label of the avant-garde, found themselves in demand. They became "starchitects."

Denver Mayor Wellington Webb, having secured the talents of Daniel Libeskind, one of the new stars, to design a major expansion of the city's art museum, opined that the eccentric-looking design would "put us on the map as a world-class destination city." Other cities and other mayors in the United States, Europe and Asia echoed Denver's Webb.

But then, inevitably, a reaction set in. Cultural commentators and critics began to complain about the Bilbao effect. (Occasionally, it is also called "the Gehry syndrome.") Conservative commentator Hilton Kramer denounced the phenomenon as "a diversion and a distraction" motivated by a desire for "tourism and trophy architecture." Architecture critic Martin Filler called it "a worldwide frenzy for museum architecture as a tourist destination and a public spectacle rather than as a home for art." Others joined the chorus.

Fundamentally, the complaints boil down to two. The Bilbao effect is viewed by many as a triumph of style over substance, a type of global branding that used to be confined to items such as fashionable shoes and whatnot. And the style itself -- especially the "signature" buildings whose complex, odd-looking forms could never have been designed and built without the aid of advanced computer technology -- is considered highly suspect.

Critic and historian Witold Rybczynski gave thoughtful voice to both concerns. "The chief aim of architecture," he wrote in September's Atlantic Monthly, "should not be to entertain, titillate, or shock viewers. . . . True architectural beauty has a particular nature: calm and considered, standing to one side of fast and furious fashion."

The critics' worries are legitimate, though greatly exaggerated. Architecture's unprecedented popularity these days is in part a media-driven fad, and the startling photogenic qualities of some of the new designs make them seem more like brand images than real buildings with walls and rooms and (usually) real-world justifications. A museum or performing arts center board that selects an architect or a design based on infatuation with the latest thing is hardly the ideal client. Some of these new museum projects -- and there are currently more than 50 underway or under consideration in the United States alone -- are sure to disappoint aesthetically and economically.

Still, blanket condemnations as a rule are unhelpful. They obscure rather than reveal. This seems particularly true in regards to the city of Bilbao, for the Guggenheim Museum and Gehry's striking design actually were part of a decisive long-term strategy to revive a fading industrial center.

An exhibition at the Art Institute of Chicago last year laid out the Bilbao planning strategy in some detail. In addition to glamorous architectural projects -- some by young Spanish designers as well as quite a few international stars -- the plan includes things such as water purification, port modernization, parks, bridges and new subway and tram lines. Even for the infrastructure projects, however, high-quality architecture was definitely a big part of the program. Much of it is of the adventurous sort the critics love to dislike.

Bilbao's list starts with Gehry's building and continues with a new airport designed by Spanish star Santiago Calatrava, subway stations by England's Norman Foster and a performing arts hall by Federico Soriano and Dolores Palacios of Madrid. Yet in places that seemed to call for more traditional approaches, the city authorities had the great good sense to commission architects capable of mixing and matching the new with the old, such as American Robert A.M. Stern's design for a riverfront retail complex close by the old city center. This is municipal planning of a high order, encompassing both substance and style -- a Bilbao effect many cities would do well to emulate.

But, taking the Gehry building as the chief model, the style issue of sculptural buildings is what Bilbao-effect critics focus on. Basically, the argument is about contextualism, about fitting the buildings to particular cities or even blocks. It is an old and important debate that actually had more bite back in the 1960s and '70s, when modern architects were in the habit of dropping sculptural buildings like alien spaceships into unsuspecting neighborhoods.

It may be that some of the starchitects and their progeny in the world's architecture schools have again lost the sense of how necessary it is to pay due respect to one's surroundings. Yet there is no general rule that says because a building is modern and sculptural, it has to be unfriendly. I.M. Pei proved as much with the East Building of the National Gallery of Art back in 1978, and many architects since then have shown themselves capable of being both daring and responsive at the same time.

Gehry himself is the prime example. It's true, as former Commission of Fine Arts chairman J. Carter Brown quipped shortly before he died, that Gehry once was "the bad boy of architecture," deconstructing both modern and traditional styles with his aggressive palette of plywood sheets and chain-link fencing. But Gehry's early works almost always engaged their settings in thoughtful ways. And, as Brown also observed, Gehry matured. His work from the mid-1980s on, from Paris to Prague, or Los Angeles to Washington, has been a study of how to respect and enliven the surroundings. And many are those who feel that his startling Bilbao building fits its central, riverside setting like a dream.

Gehry and others have done enough now to certify that being different from the norm -- even extraordinarily different -- is not evil.

For one thing, today's norm is not an ancient European city center or fine New England village. It is all that junk we're constantly throwing up along our highways, or those isolated office parks, or the could-be-anywhere buildings that struggle to make a statement -- any statement. In assessing architectural quality, it is best not to romanticize, to read the past into the present.

Ah, but isn't there a danger of romanticizing in the opposite direction, of celebrating the new because it is new? Sure, there is. One must take each situation and each building as it comes. Yet there is no denying -- or shouldn't be -- that our cities, towns and suburbs need all the invigoration, all the spirit-lifting architectural imagination that they can get.

One beleaguered city in northwestern Spain went for the best that it could find -- why shouldn't all cities do the same? That is the gist of the Bilbao effect as I see it, and I'm for it.

Frank Gehry's much-heralded Guggenheim Museum in Bilbao, Spain, which opened five years ago, has inspired plans in other cities for equally adventurous designs.Gehry, right, designed the Corcoran Gallery and College of Art's planned $120 million expansion. Below, a model unveiled last year of the atrium.