There are a wide variety of uses for wool: heavy durable rugs, soft willowy scarves and warm, chunky waterproof sweaters. It is used for crafts and felting. It can be handspun or mechanically processed. It can be a lovely heathery natural blend or a palette of bright richly dyed color.
And each of these functions is best represented by a different breed of sheep.
Wool is usually graded into three categories: fine, medium and longwool.
Fine wool has a narrow fiber that is often crimpy and very soft. It is lovely up against the skin as a high quality shirt or baby item. The softness comes at a price though-this wool is the least durable and will wear out through heavy use. The best sheep breed for good quality fine wool is the Merino.
The Merino was developed for its soft fleece in Spain dating back hundreds of years. The staple length is average at two to four inches long. The ultra-fine variety of Merino wool can be blended with cashmere or silk and sold in premium clothing lines.
A medium grade wool has a little more durability at the expense of some softness. The medium grade is preferred by hand-spinners as the fine wool can be too slippery to work with comfortably. An excellent candidate for the medium category is the Corriedale.
Corriedales were developed in New Zealand in the 1860s from a cross between a Lincoln and a Merino. It is an attractive large-bodied dual-purpose sheep. The staple length is nice at four to six inches. The wool has larger crimps giving the final product a bit of stretchiness to it. Corriedale makes wonderful hats, scarves, mittens, sweaters and lap blankets.
Long wool is the coarsest of all. It is often too scratchy to be worn directly against the skin but is very durable for rugs and heavy blankets. Longwool sheep often need to be sheared twice, or even three times a year because of the very long staple length. Two superior longwools are the Lincoln Longwool, the Cotswold and the Icelandic.
Both of these are English. The Lincoln is a huge sheep with a massive, dense, long coat. The crimp is so wide in these sheep that the wool can hang in ringlets. The Cotswold is known for making beautiful long curls for both dolls' heads and Santa beards. Both are great for felting-both at the craft and commercial levels.
Another consideration in the "best wool breed" is color. If the wool is being produced for commercial use then hands down white is the winner. White can be dyed to any color so is of use in the clothing and textiles industries. The difference in wool pool prices for the producers is in the range of fifty cents per pound for white and five cents per pound for colored, if they even accept it.
If a fleece is being produced for the hand-spinner or a more "natural" audience then colored wool does very well. Colored or natural refers to any non-white color and ranges anywhere from tan to chocolate brown, reds, silvers, grays to black. A sheep is almost never uniformly the same color so spinning their fleece creates a lovely blend or heathering within and throughout the skein.
All of the sheep listed here come in white and natural, some mixed or spotted. The best way to pick the best breed is to determine who will be consuming the wool.