Since the split, in July 2007, the average real-estate sales price in the 10065 has hit $2.9 million — topping 10021’s $2.2 million average, according to Streeteasy.com, a real estate-tracking Web site.

The hot ZIP’s stock continues to soar, too — with the current market price for homes selling at an average $4.1 million, nearly $1.5 million higher than residences in 10021.

Moviemaker Spike Lee, The Donald’s ex, Ivana Trump, corporate raider Henry Kravis, Revlon’s Ronald Perelman and NBC “Today” show host Matt Lauer all reside in the flush 10065 neighborhood, which spans 61st to 68th streets from Fifth Avenue to the East River.

Coveted real estate in the 10065 includes The Pierre hotel, whose penthouse is on the market for $70 million, and the renovated Lexington Avenue Barbizon Hotel, with apartments for sale for $12 million.

Since July, 10021 hasn’t been able to keep pace, despite being home to 740 Park Ave., once home to John D. Rockefeller and Jacqueline Kennedy Onassis, and where the city’s richest man, billionaire businessman David Koch, hangs his hat.

Up the street, Brooke Astor’s famed 778 Park Ave. duplex just hit the market for $46 million this past month. And real-estate tycoon Aby Rosen is asking $75 million for his town house at 22 E. 71st St.

“People work their whole lives to get into the 10021 ZIP code” — which now covers 68th to 76th streets from Fifth Avenue to the East River, said Brown Harris Stevens Realtor Nancy Candib. “They were upset when it was taken away from them.”

In July, the US Postal Service carved up the historic 10021 ZIP code, which once stretched from 61st to 80th from Fifth Avenue to the East River, into three sections, creating the new 10065 ZIP code and its smaller cousin, the 10075, the area from 76th to 80th.

But now, those who ended up in the new 10065 are lording it over the 10021.

Parker and Broderick keep a running count of these changes, a mutual mourning for the transformation of their neighborhood into a luxe, tree-lined shopping mall. She knows this sounds absurd coming from her, that people blame Sex and the City for the ruination of the West Village; even Broderick says, “That’s your fault!” when he sees a thong poking up from low-slung jeans, and her close friend John Benjamin Hickey, an actor, longs for the days before “those girls on buses.” Parker clarifies that she doesn’t want to sound like Madonna bemoaning what’s happened to New York: It’s not that there’s no “creative energy” in the air, it’s simply been priced out of this particular borough.

To solve the problem, Dr. Blutt bought the two town houses directly east of his current home on East 90th Street, between Park and Madison Avenues, in order to combine the three Romanesque Revival, four-story town houses into one 17,000-square-foot dwelling. His plans have prompted protest from neighbors, who see an intrusion of a suburban-style “McMansion,” and from preservationists, who fear that they would destroy the character of the landmark-protected buildings.

“It’s an audacious proposal,” said Simeon Bankoff, the executive director of the Historic Districts Council, which works to preserve New York’s historic neighborhoods and buildings. “It’s the kind of thing that seems to be extraordinarily conspicuous consumption.”

Even by the extravagant standards set by the real estate forays of this century’s gilded elite, Dr. Blutt’s plan is unusual. Because the combination of brownstones is relatively rare, especially for conversion into a single-family home, it raises a host of questions not easily answered.

Dr. Blutt had proposed a three-story rear-yard addition that would extend some 15 ½ feet beyond the buildings’ original rear walls. He also wanted to add more than 20 feet to the height of the buildings by adding a fifth floor, as well as a concrete bulkhead for a new elevator shaft.

When Dr. Blutt’s architect presented the plans to the Landmarks Preservation Commission last Tuesday, the commission took no formal vote, but some members noted their concern about the proposed fifth floor and the character of the rear-yard addition. The commission told the architect to submit redrawn plans.

Lo van der Valk, president of Carnegie Hill Neighbors, said that since the historical preservation movement took hold in the late 1960s, the expansion of dwelling space usually took place by building up and out. For instance, during the 1990s, homeowners scurried to buy neighboring apartments, knocking down walls to scrape out a few hundred extra feet.

But neither Mr. van der Valk nor Mr. Bankoff could recall a single case of a person turning three attached brownstones into one single-family home.

Mr. Koch, who turned 83 in December, said that he had purchased a burial plot in Trinity Church Cemetery.

“The idea of leaving Manhattan permanently irritates me,” said Mr. Koch, who represented the East Side in the City Council and in Congress before being elected to the first of three terms as mayor in 1977.

Trinity Church, part of the Episcopal Diocese of New York, operates a nondenominational cemetery at Broadway and 155th Street. Trinity describes the uptown cemetery as the only active cemetery in Manhattan that is still accepting burials.

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The cemetery is on the site of one of the fiercest battles of the American Revolution. Trinity describes it as a grassy retreat, dotted by century-old elms and oaks, and “a special place of peace and tranquillity far from the chrome and glass towers of central Manhattan.”

Those buried include Clement Clarke Moore, who wrote “A Visit From St. Nicholas”; the artist and naturalist John James Audubon; the actor Jerry Orbach; and Mayor Fernando Wood, who proposed that the city secede from the Union during the Civil War and was later elected to Congress, where his colleagues censured him for intemperate remarks.

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A mausoleum at the cemetery offers above-ground niches and crypts, but only a few below-ground burial plots remain vacant. Cemetery officials said they were reserved for special citizens.

Mr. Koch chose a plot on what he described as a “small mountain” overlooking Amsterdam Avenue, and he researched the propriety of being buried in a non-Jewish cemetery.

“I called a number of rabbis to see if this was doable,” he said. “I was going to do it anyway, but it would be nice if it were doable traditionally.”

He said he had been advised to request that the gate nearest his plot be inscribed as “the gate for the Jews,” and the cemetery agreed.

He was also instructed to have rails installed around his plot, so he ordered them.

Being buried in Manhattan, Mr. Koch said, would also make it easier for former constituents to visit.