BUFFALO— If the typical middle-class suburbanite had as wide a choice as he wanted, what style would he select for his home? In 18 months of studying the housing-style preferences of homeowners in suburban tracts, Scott A. Kinzy, an architect and assistant professor of design at the State University of New York at Buffalo, discovered that modern and contemporary houses rank at the very bottom of the range of styles; nearly half the homeowners instead chose a ''farm'' or a Tudor house as their favorite.

Mr. Kinzy, with a $5,000 grant from the National Endowment for the Arts, set out in the fall of 1980 to determine whether builders of tract homes were giving American buyers what they wanted or whether there was an unsatisfied desire for houses in significantly different styles.

He made drawings of the six house styles most prevalent in recent subdivisions in the Northeast and northern Middle West - styles that he called farm, Tudor, early American, Colonial, Mediterranean and ranch. He also made drawings of two houses that contractors offer much less frequently - contemporary and modern, both more spare and angular than typical suburban tract houses.

All eight drawings were then shown, without description, to 129 homeowners in two randomly chosen subdivisions, one south of Buffalo in the town of Hamburg and the other northwest in Grand Island. The homeowners were primarily white, middle-class couples between the ages of 27 and 45, with two children on average and with incomes of $26,000 to $45,000 a year.

Contrary to criticisms sometimes aimed at contractors, Mr. Kinzy found that ''builders are providing a viable range of home styles.'' When the homeowners were asked ''if they felt their current home styles reflected their personal self-image and the image they wanted to present to others, the majority responded positively,'' Mr. Kinzy said.

The homeowners - whose tastes, according to Mr. Kinzy, reflect those of middle-class suburbanites throughout the Northeast and northern Middle West - acknowledged that their homes were not unique, but they nonetheless considered their houses individually expressive.

When shown the eight drawings, only 4.7 percent of the homeowners selected the modern house as their favorite and 7.8 percent selected the contemporary.

By far the most popular were the farm house, chosen by 25.6 percent, and the Tudor, the favorite of 23.3 percent. The third most popular was the ranch house, at 13.2 percent; the only one-story model, it was chosen by most of the homeowners over 44 years old. Mediterranean was the favorite of 9.3 percent, and early American of 8.5 percent.

Mr. Kinzy was surprised to find that the Colonial, with its symmetrical facade and its two-story columns, fared poorly, tying the contemporary as the first choice of only 7.8 percent of the homeowners.

The study suggested that the Colonial style is liked much less than many assume. Though the homeowners identified it as the favorite of most Americans, they in fact put it behind every other common tract housing style. They said the Colonial was the style they would have preferred when they were younger, but the younger homeowners found it unappealing. Mr. Kinzy concluded that perhaps the Colonial was ''too garish, ostentatious or pompous for our consumers' tastes.''

To further determine what meanings set styles hold for middle-class suburbanites, Mr. Kinzy gave a list of 24 adjectives to the homeowners and asked them to choose appropriate ones for the houses.

The flat-roofed modern house and the pitched-roofed contemporary were each called unique, but they were also called ugly, flimsy and austere. The unpopular columned house, by contrast, was described as formal, grand and high-class, some of the same words that were applied to the Mediterranean style. The early-American house with a Williamsburg influence came across as conservative, plain and durable, while the ranch was perceived as economical, modest and simple. The Tudor emerged as stylish, complex and beautiful. Finally, the popular farm house, with its generous porch, was thought of as homey, informal and durable.

''People tend to choose the style of house that their friends live in,'' Mr. Kinzy said, adding that social pressure toward conformity in housing styles appears stronger in subdivisions than in rural areas.

Suburbanites, Mr. Kinzy found, dislike subdivisions in which most houses are in one style. Satisfaction increased when homeowners altered the builder's model or obtained a custom design.

Even so, Mr. Kinzy said that for families with incomes of $26,000 to $45,000 a year, ''the findings clearly indicate that home style is not a critical factor when choosing a home, when compared to other functional issues.''

Overall, style ranked ninth in importance. The most important factor was price, followed by house quality, the area, maintenance and durability, resale and investment value, site, neighborhood amenities and privacy. As to what would be more important for a new home today, the most common answer was energy efficiency.

Illustrations: drawing of houses