As the Rufus S. Lusk & Son real estate reporting service said, the Pennsylvania Avenue Development Corp. "should have shopped at K mart and saved $1.7 million!"

Just eight months ago, a limited partnership calling itself 702 E Street Associates, including Barry Stern, Robert Moran, Jerome Golub and Max Berg, bought the old S. S. Kresge Co. store at the same address from K mart Corp. (Kresge's parent company) for $2 million.

Now the partnership has sold the 7,221-square-foot site to PADC, which oversees development along the avenue and its environs, for $3.74 million, a $1.74 million profit for the partnership's eight-month ownership.

A PADC spokeswoman said the agency bought the store to add to a collection of buildings it owns in the block bounded by Seventh, Eighth, D and E streets NW and soon will announce a design competition for redevelopment of the square. The old Lansburgh's Department store, more recently used as D.C. government offices, is also on the same block.

The spokeswoman, defending the purchase price, said that PADC by law is "required to pay fair market value for properties it buys based on two appraisals, which would have been done independently of recent sales."

The American Institute of Architects' Foundation Forum for Architecture recently asked its College of Fellows to name the 10 best buildings in America, and it turned out that four of the buildings selected in the survey are in the greater Washington area.

Here's the list: Falling Water, Bear Run, Pa.; Seagram Building, New York; Washington Dulles International Airport; the University of Virginia; the Robie House, Chicago; Trinity Church, Boston; East Wing of the National Gallery of Art; Rockefeller Center, New York; Johnson Wax Building, Racine, Wisc., and Monticello.

Exactly a century ago, the same 10-best-building question was posed by the American Architect and Building News and here were the results: Trinity Church, Boston; the U.S. Capitol building; the W.K. Vanderbilt House, New York; Trinity Church, New York; Third Judicial District Courthouse, New York; the Connecticut State Capitol, Hartford; Albany City Hall, Albany, N.Y.; Sever Hall, Harvard University, Cambridge, Mass.; New York State Capitol, Albany; Town Hall, North Easton, Mass.

IN THE BUSINESS . . . Leo A. Zickler, president and chief executive officer of Oxford Development Corp., has been named 1986 Man of the Year by the National Housing Conference . . . Mount Vernon Realty, with 56 offices from Baltimore to Richmond, has now opened one in Sarasota, Fla., where the firm's president, W. Howard Rooks, has maintained a home for 15 years . . . Long & Foster recently awarded more than $500,000 worth of prizes to its top sales associates and managers, including 47 who won a trip for two to Ireland in October . . . J. Anthony Romero III and Joseph L. Donnelly have formed Romero & Donnelly Inc., to specialize in commercial investment real estate . . . Construction has started on the first phase of the Washingtonian Center, a 211-acre, $500 million mixed-use project on I-270. The complex eventually will have 4.5 million square feet of office, retail-commercial and hotel-conference space and 1,400 housing units . . . The appraisal firm of Joseph J. Blake & Associates Inc., based in Woodbury, N.Y., has opened a regional office here, with Dennis Duffy the principal and regional manager . . . Julien J. Studley Inc., a commercial leasing firm, said that during the first four months of the year, a total of 2,215,126 square feet of office space were leased in the District, compared with 2,286,141 in the same period a year ago . . . The Northern Virginia Board of Realtors has named Thomas M. Stevens as "Realtor of the Year." The board reports that 13,513 homes and condominiums were sold in Northern Virginia in the first five months of the year, up 39 percent over the same period a year ago.

PERSONNEL FILE . . . Federal Home Loan Mortgage Corp. has named Anthony J. Sulvetta as vice president for corporate finance. . . . James C. Wheeler, formerly vice president of real estate for Peoples Drug Stores Inc., has joined Signet Cos. in the same position . . . Ivor B. Clark Co., a real estate and investment firm in the District, hired Bromley K. Smith Jr. as vice president in charge of the real estate investment banking group. Smith was senior vice president of Brookshire Hotels Ltd.