(MONEY Magazine) – Last year, the typical American family spent about $282 on furniture, though even at that level, sales totaled $26.8 billion. This year, the big drop in interest rates -- almost a point since Election Day -- is helping millions of families to buy new homes or save money by refinancing mortgages. Either way, Americans are on a furniture-buying spree that is increasing sales 15% to 20%, says Furnishings Digest, a trade newsletter. The result: a projected four-year high of $31.5 billion in sales, or $332 worth of new furniture per family. Does that translate into a new dinette set for every breakfast nook? Hardly. Furniture isn't an every-year purchase for everyone, even in a year like this one. Reason: Furniture lasts and lasts -- 31 years, on average, in the case of dining tables. Better yet, if you choose wisely, the furniture you buy today will not only endure but will appreciate -- perhaps doubling in value, after inflation, over 30 years. Furniture with investment potential includes contemporary originals and fine reproductions. Whatever its provenance, though, collectible furniture should boast the following features: -- Purity of design. Choose extremes -- classic styles such as the Queen Anne copy on page 176 or items that are the leading edge for their time. ; -- Superb craftsmanship. Whatever the style, look for painstaking construction with strong, tight joints. Details count. Hand-cast, solid-brass hardware gains patina with the years. -- Natural or scarce materials. On repro furniture, woods as well as decorations should be appropriate to the piece's period, and rare materials add value. For a Hepplewhite cupboard, for example, cherry or pine is fine, but scarce curly maple is better. On contemporary furnishings, anything goes if the materials have character. -- A recognized designer's imprimatur. A tubular-steel chair made to Marcel Breuer's design will outlive any knockoff. A perfect Hepplewhite or Sheraton repro holds value; a ''Heppleton'' hybrid just gets old. Over the next six pages we offer a portfolio of pieces that meet these criteria in prices ranging from $93.75 to $15,000. Our sampler includes: -- Eighteenth- and 19th-century reproductions, pages 176 and 177. -- Early modern classics from acclaimed designers and architects, pages 178 and 179, built to each master's specifications. A fee of 5% to 10% is paid by the manufacturer to the designer's estate or foundation. -- Contemporary furnishings, on pages 180 and 181, from workshops, studios, galleries and artists. How should you choose when offerings range from neoclassic to neo-geometric? Advises Edward S. Cooke, Yale's associate professor of American decorative arts: ''Visit museums, read books to learn about styles but, finally, buy what you love. The objects may or may not be financially valuable for your grandchildren -- but they will develop history as they pass down the generations.''

18TH- AND 19TH-CENTURY REPRODUCTIONS Usually, 25 or more years must go by before fine reproductions appreciate. Sometimes it happens sooner: In 1991, Sotheby's in London auctioned a set of 12 George II mahogany chairs made in 1984 by Kindel Furniture of Grand Rapids for (pounds)10,000 (about $17,000 then) -- fully 20% more than the original owner had paid. But don't confuse such topnotch repros with mass-produced ''traditional'' furniture, which isn't worth much on resale. ''You're looking for hand craftsmanship,'' says Edward Herguth at New York City's William Doyle Galleries. Line-for-line copies are likely to hold value better than pieces done in period style. Master furnituremakers can be found through museums and antiques magazines. One is Robert Whitley of Solebury, Pa. (215-297-8452), whose repros grace Philadelphia's Independence Hall and cost $2,000 to $12,000. You'll find more choices from licensed reproductions of museum pieces, which cost $1,500 to $30,000. Four quality collections: the National Trust for Historic Preservation (which owns historic homes across the U.S.) and Delaware's Winterthur Museum, both of which license repro rights to Kindel (616-243-3676); Colonial Williamsburg (Baker Furniture; 616-361-7321); and the Smithsonian Institution (Century Sutton; 800-852-5552). Manufacturers can supply names of local retailers. Typically, country-style repros, often derived from colonial American or Shaker styles, are produced by workshops.

TWENTIETH-CENTURY MODERN In the first third of this century, while Pablo Picasso was exploding the human figure into spare parts, architects at the Bauhaus, the revolutionary German design school, were marrying art to industry. Finnish architect Alvar Aalto banished decoration while Swiss architect Le Corbusier declared the house ''a machine for living.'' And Bauhaus brethren Walter Gropius and Marcel Breuer experimented with man-made materials. Over in America, from about 1910 through the '50s, Frank Lloyd Wright crafted furniture to complement his Prairie school architecture. In addition, furnituremaker Gustav Stickley and his brothers produced mission-style wood pieces that celebrated nature. Originals of all these 20th-century classics now command princely sums. In 1988, for example, Barbra Streisand paid a record-setting $363,000 for a 1903 oak-and-wrought-iron Stickley sideboard -- well above the top $264,000 paid a year earlier for a Frank Lloyd Wright chest. Here we show licensed copies made to original specifications. Many such pieces carry serial numbers and are stamped with the master's signature. The distributors we list may provide names of retailers near you. List prices are often discounted 10% to 40%. Unlicensed knockoffs may cost less but are usually inferior. In a metal chair, for example, ''the thickness of tubing and quality of chrome plating affect how long the piece lasts,'' says design consultant Stephen Kiviat.

CONTEMPORARY AND STUDIO Hunting for furniture that will appreciate among present-day designs means entering new territory. History has already passed judgment on Sheraton and Stickley, but the investment track record for contemporary designs, which include postmodernism as well as other styles, is short -- dating from the late 1970s. With contemporary items, your grandchildren are truly the jury. Still, the basic rules apply: Look for bold designs meticulously executed. And make sure you really want the furniture to join your family. What you'll discover in the contemporary marketplace is a kaleidoscope of styles with a few common themes. Today's pieces tend to be rooted in the past, yet their design acknowledges man-made materials or technological innovations. For example, Sottsass' postmodern 1981 lamp, far left, nods to 1950s modernism as well as to the pop art '60s. The best contemporary work carries the stamp of its maker. Says Terence Riley of the Museum of Modern Art in New York City: ''Consumers don't want injection-molded plastic anymore. They want to look at a chair, even if it's machine-made, and see the person behind it.'' You'll also find that the hand of a recognized artist adds value.