Thanks for asking, and thanks for refusing to consider declawing, which I consider a draconian solution for "illegal" scratching by cats.
As you probably already know, cats do need to scratch, and sometimes they will scratch furniture. And of course, with furniture upholstered in high pile fabrics, such as corduroy, not only can it be damaged by cats' claws, but will also attract cat hair like magnets. Although you didn't ask, I can give you my unqualified opinion, based on personal experience, that velour is the worst upholstery in a home with cats. We had a velour sectional for several years, and it wasn't long before the sides were ragged and tattered from cats clawing it. Also,the seating cushions had to be vacuumed regularly to remove the cat hair. Most heavy pile upholstery falls into this category.
The next-best covering for sofas and chairs is Naugahyde. We had a Naugahyde couch several years ago and it held up pretty well. However, eventually even short claw marks would suddenly turn into triangular tears.
After several decades of experience with various furniture coverings, we opted for leather about three years ago, and it has stood up beautifully. Our cats rarely scratch it. Their claws do dig in when they jump up to the arm of the sofa and leave tiny holes. But for the most part, these holes are invisible to the eye. And, unlike Naugahyde or other leather imitations, the holes do not turn into tears.
Leather has the added advantage of being easy to clean. Accidental cat (and people) messes, such as vomit, can be picked up with a paper towel, and the residue cleaned with a damp sponge. For more information on cleaning leather furniture, see Abe Abbas's article on the About.com Furniture web site.
I'd be remiss in closing without mentioning other ways to keep cats from illegal scratching of furniture. Most cats will leave furniture alone if they have a variety of scratching posts available. Other means of limiting damage to furniture (and tender skin) from cats' scratching include trimming claws and/or applying plastic nail covers.