Whether the White House end of the rebuilt Pennsylvania Avenue will be common commercial, modified mordernistic or excitingly dramatic in its architectural character, is to be decided by the directors of the Pennysylvania Avenue Development Corp. Tuesday.

They are to make the final selection in a competition for the restoration of the historic Willard Hotel and the development of the adjacent land.

The first Council on Pennsylvania Avenue, appointed by President Kennedy in 1962, recommended that the Willard Hotel, along with the entire block between 15th and 14th Street, be demolished to make room for a vast "national Square" at the White House gate.

Yielding to citizen opposition and a new public attitude in favor of historic continuity rather than cataclysmic urban renewal, the Develop ment Corporation, established in 1972, all but reversed the original plan for the avenue. (The most drastic reminder and most prominent product of that plan is the FBI Building at 10th Street.)

The new emphasis is on amenity, rather than pomposity, on preserving buildings that represent different eras and styles, rather than imposing arrogant modernism on the "main street" of the nation.

The new approach has worked. While the old plan left Washingtonians and Congress indifferent at best and attracted no private development, the new one not only "stirred men's blood," to use Daniel Burnham's famous phrase, but also stirred up congressional appropriations and-at latest count-some $180 million of assured private investments along the avenue.

A symbolic, as well as economic, centerpiece for the Pennsylvania Avenue renaissance is a restored Willard in a lively and attractive new setting. The esthetic and popular success of the Willard complex will set the tone for everything else that is hoped and planned for the avenue.

One indication that hope is justified is that nine teams comprised of highly respected architects, developers and hoteliers responded to the corporation's call for detailed proposals. Earlier this month, the corporation narrowed its choice to three.

The scheme that strikes me as common commercial, a piece of K Street banality wedged betwee the Washington Hotel and the Willard, is proposed by architects Cossuta Associates (who gave us the Christian Science Church on 16th and M Street NW), Hellmuth, Obata & Kassabaum (who gave us the Air and Space Museum) and David N. Yerkes, a local architect much acclaimed for the new buildings at Madeira School.

The developer on this team is the ubiquitous Oliver T. Carr, who also wants to rebuild the block opposite the Old Treasury Building on 15th Street if the would-be saviors of the long-lost Rhodes Tavern, which is now a dingy news stand, will let him. The hotel on this team is the Intercontinental Hotel Corp.

In addition to restoring the Willard, these people would give us nothing much more than a bland office building with a penthouse higher than the Willard, zebra fenestration, and 40,000 square feet of retail space.

One wonders how this unimaginative proposal ever made the three finalists, while the enchanting design by architects Hartman/Cox was thrown out. The reject replicated the Willard's Beaux Arts facade in a respectfully simplified manner, proposing for this stretch of Pennsylvania Avenue some of the delightful uniformity of the Rue de Rivoli in Paris.

Out-of-town critics with no knowledge of Washington's cosmopolitan objectivity whisper that Oliver Carr made the finalists only because he is a local boy. But I pass this vicious nonsense on only to show how badly this city is still misunderstood in the rest of the country.

The modified modern proposal was submitted by architects Welton Beckett Associates of New York, one of the largest firms in the country. The developers are a Chicago syndicate named MATS. And the hotelkeepers are Trust Houses Forte, a British organization.

The Beckett scheme shows a sensitive understanding of what is needed on what may be, or should be, the most important city block on this continent. It is, to begin with, the only one of the three which would keep and restore the charming old Occidental restaurant along with, I should hope, the Occidental's good, no-nonsense cuisine.

Beckett and teammates would also give us apartments in addition to offices, recognizing that you cannot "revitalize" downtown, here or anywhere else, without people who don't just park and shop, but also live there. The British hoteliers, who also run the Pierre in New York, furthermore, promise to make the Willard the first class hotel it should be.

Beckett's architecture is varied and tries to fit in with the Willard and Occidental, mostly by sporting mansard roofs. This strikes me as somewhat clumsy. There is an insipid entrance to the inner court shopping mall that is disturbingly cheap-looking.

If the Beckett proposal is adequate, the third finalist's is exciting-a work of inspired architecture. It is daring, not in the sense of a stunt trying to be original for the sake of originality; it is daring in its solution of the problem of placing a new building between two old ones with harmony and interest.

The architects of this scheme are Hardy, Holzman, Pfeiffer Associates of New York, who designed the American Film Institute theater in the Kennedy Center and the all too "with it" Orchestra Hall in Minneapolis. They also sensitively restored the Carnegie Mansion in New York City to serve the Cooper-Hewitt Museum of Design and the St. Louis Art Mansion. The Willard design is surely the most brilliant accomplishment so far of this up-and-coming young firm which is securely "post modern" without having to assume this uncertain label.

Hardy, Holzman, Pfeiffer's developer is Stuart S. Golding of Clearwater, Fla., and the Fairmont Hotel management of San Francisco.

The architects' inspiration was to pay homage, as it were, to the Willard by letting it carry the visual burden of the busy 14th Street-Pennsylvania Avenue corner. They accomplished this by placing the addition-the building complex between the Willard and Washington hotels-on F Street. This means that the main addition, another hotel, is recessed and at a slight angle. It is built on the rectangular grid, while the old Willard follows the diagonal of Pennsylvania Avenue.

But after an interval, which gives the hotel addition a view on the avenue, the new building moves forward in three successively smaller and lower steps to align the whole ensemble with Pennsylvania Avenue. The void created by the setback is filled with a three-story structure, housing a lobby under a garden terrace and swimming pool.

All this is designed in the luxuriant, literate Beaux Arts-style of Henry J. Hardenbergh, who built the Willard as well as the Plaza Hotel and Dakota Apartments in New York City. Hardenbergh was the master of elegantly turned corners, so Hardy, Holzman, Pfeiffer give us corner upon corner under a shower of mansards.

The site slopes down some 17 feet from F Street to the avenue. Hardy, etc., take advantage of this by giving us a procession of exterior stairs that ascend from the avenue to the addition, passing an agglomeration of boutiques. It adds a touch of elegance.

It may add a touch of silliness, however, to have the entrance to this terraced promenade through a free standing portico, a piece of stage set, a folly.

In a city that takes itself much too seriously, architecturally and otherwise, I welcome the exuberance of this proposal.