To drugstore chain executives, opening plenty of big new stores with drive-through windows and ample parking is one of the best ways to deal with the needs of time-pressed customers.

But to some historic preservationists, these stores are a blight -- out-of-tune buildings that overwhelm their neighbors.

In a list it plans to release today, the District-based National Trust for Historic Preservation singles out chain drugstores as threats to "Main and Main," the mythical prime intersections of America's downtowns. The biggest drugstore chains -- Walgreens, CVS and Rite Aid -- have announced major expansion plans that could add thousands of new locations nationally in the coming years.

"Main and Main" tops the Trust's list of "America's 11 Most Endangered Historic Places," an annual endeavor that the well-respected preservationist group uses to draw attention to its cause.

The group claims that the list, in its 11th year, has "spurred some key victories for endangered sites," including Congressional Cemetery in Washington, which was on a past list and this year received a $1 million federal matching grant for maintenance.

The list is also one of the National Trust's most reliable devices for drawing attention to its causes. For instance, cable's History Channel has already arranged to run an hour-long documentary at 10 p.m. Thursday on the sites on the new list.

The list can also be controversial. The Pennsylvania Builders Association and the National Association of Home Builders have protested the inclusion on the list of Pennsylvania's Lancaster County, home of the Amish. The designation "is sensationalistic and is aimed at stopping growth rather than finding solutions to growth challenges," according to the builders.

Preservation concerns often come in conflict with growth, not only in Lancaster County, but also at the "Main and Main" downtown areas where drugstores are opening.

"These chains are targeting key locations, often where there are historic structures," said Richard Moe, president of the National Trust.

The group is particularly concerned about drugstore locations in established downtowns, rather than those in far suburbs that may have few historic structures. That presents a particular dilemma: The long decline of these downtowns has itself been a serious threat to historic buildings. Chain drugstores are frequently among the first businesses to try to move back into a downtown that may be on the way back up.

"While we welcome their wanting to come downtown and add to economic vitality downtown, we're very concerned about the high incidence of historic structures that have been destroyed," Moe said.

The drugstore chains defend their expansion decisions. "We do not target buildings or specific historic buildings for sites. We target intersections or locations," said Michael Polzin, a spokesman for Illinois-based Walgreen Co., the nation's largest chain. "Our approach throughout this decade has been to find corner sites at major intersections where we can put free-standing stores."

Existing buildings usually don't meet the company's needs, according to Polzin. "On occasion we may be able to rehab it and use what's there, but primarily what's there will not fit our basic configuration," he said.

"We look for the locations that are convenient for customers," said Todd Andrews, a spokesman for Rhode Island-based CVS Corp., which has been the most aggressive chain in the Washington area. "Customers like the stand-alone configuration of drugstores rather than the attached or mall configuration. Stand-alone drugstores tend to be a little bigger -- like 10,000 square feet. It has more parking, has longer hours, sometimes it has a drive-through."

"Easy access" is a top customer demand, said Jody Cook, spokeswoman for Pennsylvania-based Rite Aid Corp. "Our stores need to be convenient and accessible," she said.

"It is Rite Aid's policy not to tear down any structures currently listed on the National Register of Historic Places," she said. "Now, recognizing that certain buildings may have historic significance to local communities, where it is economically and logistically feasible we will try to come up with a mutually agreeable solution."

According to Moe, preservationists don't want to block the drugstores, they simply want the chains to consider the architectural and historic significance of buildings and neighborhoods instead of demolishing them. "We want them to go in, but we want them to go in with flexible design," he said.

"A lot of chains have these formula designs, but that's not the only way to do it," said Moe. He cited Starbucks and Banana Republic as national chains that have demonstrated sensitivity to preservation concerns. "They've found they're much more warmly received in a community when they do that."

CVS's rapid expansion has sometimes annoyed and even infuriated neighbors in Washington, but according to the National Trust, some of the buildings the chain has occupied here are models for how to open a drugstore in the city.

The most controversial recent CVS opening was that chain's 1997 takeover of the darkened MacArthur Theater in Northwest Washington. Although neighbors vocally protested the change, a National Trust publication, "Better Models for Chain Drugstores," showcases the renovation because at least the exterior and some of the lobby remain intact.

"We would have preferred it remain a theater, but sometimes, if there are other uses, it needs to be adapted," Moe said. "The good news is that the structure survived."

Endangered Places

As named by the National Trust for Historic Preservation:

1. The corner of "Main and Main," representing downtowns throughout the country threatened by chain drugstore expansion

2. Richard H. Allen Memorial Auditorium, Sitka, Alaska

3. Angel Island Immigration Station, San Francisco

4. Country Estates of River Road, Louisville

5. Four national historic landmark hospitals, various locations, New York state

6. Hulett Ore Unloaders, turn-of-the-century riverfront industrial machinery in Cleveland

7. Lancaster County, Pa., traditional home of the Amish and Mennonite sects

8. Pullman Administration Building and factory complex, Chicago

9. Arts and warehouse district, San Diego

10. Travelers' Rest, believed to be where the Lewis and Clark expedition camped twice, Lolo, Mont.

11. West side of downtown Baltimore, a commercial district where revitalization plans may threaten many buildings

CAPTION: CVS took over the darkened MacArthur Theater in Northwest Washington in 1997, but it left the exterior and some of the lobby intact.