“Where else around here can you get that kind of food?” she said.

Up and down the prime retail stretch of Madison Avenue, new luxury European designer emporiums are popping out as prolifically as celebrity babies. Meanwhile, the old-fashioned coffee shop, one of New York’s most quintessential and beloved establishments, has become an endangered species, so imperiled that many neo-New Yorkers now consider the phrase “coffee shop” synonymous with—the horror!—“Starbucks.”

Also gone, since the summer of 2006: Soup Burg on 73rd Street. Threatened: 3 Guys, between 75th and 76th. Where are Upper East Siders supposed to get a decent grilled cheese, chicken salad or BLT? What about a cup of coffee that doesn’t taste artfully over-roasted and come served with a world-music soundtrack? How about a sense of community that hasn’t been generated in some corporate boardroom?

“When Gardenia’s doors closed, it closed a piece of our lives,” said Jill Simonson, director of corporate relations at Dress for Success, who used to eat at the diner several times a week when she worked at Ungaro, across the street, and became friends with the owners.

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The Last Coffee Shop

“I’m starving!” wailed Muriel Melendez, assistant store manager at the women’s clothing boutique Marina Rinaldi, also across the street. “I really miss the convenience … and being known by name.”

“I went to stop by for lunch the other day and was shocked that they weren’t there,” said Albert Hadley, the well-known interior designer. “It’s a great loss. I went there several times a week. We all miss a place like that. It was very popular with lots of people.” Mr. Hadley said that he’s been eating at his desk of late.

“The area is not the same without Gardenia,” said Joyce Black, who has lived in the neighborhood for about 30 years. “Where do you go now? When I walk past it, I feel sad.”

BLT’S WITH J.F.K. JR.

According to George Katsichtis, 24, one of the family members who ran the Gardenia, it was his own uncle, owner of the building, who decided to renovate and lease the property to a more profitable mystery tenant. “We were devastated,” young Mr. Katsichtis said. “It was our bread and butter. We had three generations of customers.”

Mr. Katsichtis is currently looking for space to open his own restaurant. “Not a diner,” he said. “Something trendy.”

John Zannikos and Spiro Argiros, the owners of 3 Guys for 30 years, said that they are hoping to renew their lease, though their landlord, William Friedland of Friedland Properties, wants to raise their rent to three times more than what they are currently paying. “We don’t want people to lose their jobs,” Mr. Zannikos said.

“The city is turning into a nightmare with rents,” said Mr. Argiros. “We hope our landlord will be understanding that this is an institution, not just a restaurant.”

Mr. Friedland, who also owns the building that formerly housed Soup Burg, refused to comment.

Wendy Chaiken, 32, a local mother of three young children, shudders at the prospect of losing 3 Guys. “There are so few places that accommodate strollers,” she said, noting that the popular restaurant Serafina nearby has steep stairs. “And you can’t just order a grilled cheese at places like Serafina!”

Indeed, 3 Guys has become a veritable hot spot for uptown yummy mummies and their broods, as documented by Chanel scion Jill Kargman in her novel Momzillas: “This was the epicenter of mommypalooza,” she wrote. “All roads lead to 3 Guys.”

“It’s such a scene for the preschool set,” said Ms. Chaiken.

“You feel like you run into everyone,” said Samantha Kaufman, another local mom.

For some, it was a bit much to face at breakfast. “When I lived near 3 Guys, I really didn’t go there much because it was too much of a scene,” said Renee Tobin, 37, a mother of two (with another on the way). “I wasn’t interested in getting that dressed up in the morning.”

But most customers protest that these diners are special precisely because you don’t really have to dress up to eat there. Even Ladies Who Lunch, after all, don’t always feel like enduring the social scrutiny at La Goulue or Nello, especially if they are still in their Pilates pants, pre-blow-out and sans makeup.

“Sometimes when I went to Gardenia I didn’t look good, so I’d hide behind my bag,” Ms. Black admitted.

In their own version of causal “Fry-day,” high-society ladies and gents, celebrities and politicos have been scarfing down burgers at these Madison Avenue diners for decades. “Jackie Kennedy and J.F.K. Jr. used to eat here,” Sergios Despotis (known as Steve), owner of Viand on 78th Street for 35 years, said proudly. “Caroline still comes in. And Mayor Bloomberg, who lives right down the street, comes in two to three times a week for breakfast.”

“Mayor Bloomberg practices his Spanish with me,” piped up Viand waitress Mirta Alvarez.

Ms. Kaufman’s mother, Susan Leibowitz, recalled having lunch at 3 Guys with her daughters one day when the late socialite Nan Kempner came over and told her that this was her favorite coffee shop. “Her family was in from San Francisco—and she took them to 3 Guys!” she said.

Some of Gardenia’s celebrity patrons, meanwhile, included Mayor Rudolph Giuliani and Sarah Jessica Parker. “She got her hair done at the salon upstairs”—John Frieda—“and was supersweet,” Mr. Katsichtis said.

In the homey atmosphere of these coffee shops, boldface names literally rub elbows with doormen, and elderly patrons befriend young children.

“My daughter Grace regularly sees this elderly couple at 3 Guys who are always there at 12 o’clock,” Ms. Chaiken said. “As my mother said, ‘They take you from cradle to grave.’”

But can the Madison Avenue coffee shop itself fend off the Grim Reaper?

Dino Bastas, an owner of the New Amity Restaurant near 84th Street, which has been operating for 30 years, said his lease is up in May 2008, and he knows there will be a significant increase in rent due to market values. “We’ve attempted to talk with our landlord,” he said, “but this is a tough business. Corporate entities are willing to pay to have a presence on Madison Avenue. And landlords don’t want restaurants as tenants. A restaurant is not sexy.”

Viand’s landlord of 40 years, Dr. Edward Soufer, knows that leasing to a restaurant is difficult. “The insurance goes up,” he said. “Fumes, bugs and rodents can be a problem. It’s not as clean as having a clothing store in your building.”

Still, Dr. Soufer has a soft spot for his tenants, and even though Citibank made him an offer for the same building, he refused to sell out. “They were willing to pay anything! But I like Steve, and I told him as long as I’m alive he’s going to be here.”

Perhaps that’s why Mr. Despotis is magnanimous about landlords raising rents. “It’s a business,” he said. “The market is crazy.”

THE $7.95 GRILLED CHEESE

Of course, with exorbitant rents come exorbitant prices, at least for diner food. “If our rent is raised our prices will have to go up,” Mr. Bastas said. Mr. Zannikos of 3 Guys agreed that he would probably have to raise prices if his rent goes much higher. “The workers from the neighborhood who purchase food here may not be able to afford it then,” he said. “We’re already known as the most expensive coffee shop in the city because of our location.”

“The prices are so high already that it’s pretty insane,” complained Ms. Chaiken. “I took the kids to Sette Mezzo [at 71st Street and Lexington], and the lunch there was only nominally more expensive.”

“It gets to a point where you might as well be eating at Bergdorf’s,” said one neighborhood mother. “But,” she pointed out, “at 3 Guys you can order a salad while your kids get grilled cheese and fries.”

“How much can you charge for a grilled cheese?” wondered Mr. Despotis. (Try as much as $7.95 at some of these joints, and that’s before the leases have been renewed.)

Still, many patrons refuse to stand by and watch their favorite haunts be eviscerated by retailers flush with the almighty euro. Some have turned to the New York City Council. “This is a difficult social problem that needs to be addressed on a broader level,” said Councilman Daniel R. Garodnick of District 4, which includes the Upper East Side.

Mr. Garodnick noted that the Council’s small business committee is considering ways to encourage restaurant owners to stay in the community, such as zoning changes and tax incentives. “These coffee shops are community gathering places,” he said. “They give character and life to an area. We need to be careful, or they will be lost.”

It appears that the diners, unlike certain beloved neighborhood institutions, have not quite made it to landmark status. “The law does not give us the authority to tell a property owner how his or her building can be used,” said a spokeswoman for the Landmarks Preservation Commission. Roger Lang, director of the nonprofit New York Landmarks Conservancy, said that his organization focuses on architectural and not cultural significance. “We’re building huggers,” he said.

However, concerned citizens can advocate for favorite endangered retail establishments through a project called Place Matters (www.placematters.net), formed jointly in 1998 by the Municipal Arts Society and a national not-for-profit called City Lore. So far, Juniors in Brooklyn and Minetta Tavern in the Village have made a citywide survey called Census of Places that Matter—why not 3 Guys, Viand and the Amity? And hey, while you’re at it, stick the Nectar on 82nd there, too!

“Other cities have been able to support small business owners by establishing a progressive tax,” remarked Vanessa Gruen, director of special projects at the MAS, “but the New York State Constitution does not allow it.”

And so for the time being, Madison Avenue shoppers may have to trudge a little farther to find the greasy fare and casual atmosphere they have enjoyed for years. “We need coffee shops for quick, informal lunches and as a safe haven for teenagers,” Ms. Leibowitz implored. “Plus”—oh, that treasured New York rite!—“you can go in alone and sit at the counter!”

“People come in and ask where Gardenia is,” mournfully said Joseph Wohltjen, a salesman at Searle, next-door neighbor to the doomed diner. “It’s definitely missed. It’s retail or nothing now.”

But no matter how many fabulous new European designer boutiques open along the Avenue, even the most intrepid fashionistas need to eat at some point. And right now, the pickings are as slim as the waifish women in the hood.

“The people who live and shop around Madison Avenue still want food,” said Noufri Argiros, son of Spiro, the 3 Guys co-owner. “And you can’t eat a Prada bag.”