Wool is the original carpet fiber. It is still the standard of the industry. It's beautiful, but expensive. In fact today, it represents only about 1% of the carpet market. I would recommend buying a wool carpet only if you intend to keep it for a long long time. A good wool carpet will cost $40 or more per square yard.

Polyester takes dye well, but it is not very durable. It is a good choice for a low traffic area, however. As you might imagine, it is less expensive than some other fibers.

Olefin/Polypropylene is moisture resistant, and resistant to fading. It is a good choice for a damp basement or for use as indoor/outdoor carpeting.

Nylon represents about 90% of the carpet market. But beware, all nylons are not the same. Look for the manufacturer's trademark. New generation nylons are especially designed to resist static, matting and crushing, and soil and stain.

Recent introduction on the market are stain resistant carpeting that repels most common household stains, and alleviates the concerns most people have using carpeting in high-spill areas.

A well constructed fourth generation nylon carpet will cost $20 or more per square yard. If you like the look of wool--but not the price--ask for nylon in a de-lustered finish.

Twisted fibers, like a spring or a curl, are resilient. They bounce back after being crushed. Sometimes a tighter twist can make up for a lack of density in terms of performance.

Frieze is the most tightly twisted style. It has a pebbly informal look and is hard-wearing and dirt-hiding. It is good for high-traffic areas. The Frieze is the most rugged of the cut pile styles.

Saxony has a medium amount of twist. You can recognize this style by its appearance. You can distinguish the ends of the fibers from one another.

Velvet Plush has almost no twist. The fibers blend together into one smooth velvety look. This luxurious look is not for heavy traffic. High density will increase its durability. Plush carpets tend to show footprints unless the fibers are de-lustered.