*disclaimer: the follwing is full of typos, but spell-checkers are for work/school and I just don't care*
Each fabric has it's own good/bad properties...
Synthetics
The good--depending on the material and techniques used in the fabric's processing, a synthetic fiber can be very strong, lightweight, have high insulative or cooling properties and be moisture wicking or water repellent.
The bad--No one piece of equipment will fill every role. I have Joe Rocket motorcycle gear that is highly abrasion resistant, but I wouldn't expect to get much use of it camping or hiking. In the same turn, I wouldn't expect much protection from my The North Face Denali jacket when speeding along at 70mph on two wheels.
The ugly--It's all about the threads and weave. Unless manufactured specifically, synthetics often have little beathability or wicking properties in and of themselves. The magic properties of synthetics are based on the type of material used to make the threads, how the threads are formed, shaped, and how they are arranged.
The same fibers in your fancy super-absorbant microfiber towel would not bode well in a Mountain Hardware rain jacket, but they are often made out of similar base components. For this reason, the quality and properties are often determined by the manufacturer and carefull attention to details are important. Cheap usually means junk.
Synthetics often break down under UV exposure and have a definite use-of-life. Most synthetics are flammable because they are usually oil based. Also, they are often more delicate than natural fibers.
High quality synthetic equipment is usually expensive.
Cotton
The good--Inexpensive, long/hard wearing, and naturally breathable. Makes excelent material for either riding a motorcycle, typing a report at work or entering into a contest featuring a t-shirt and getting wet (like running a marathon /ubbthreads/images/graemlins/wink.gif ).
Cotton clothing can be found all over the world and often does not require special handling or care.
Also, I look good in Dockers and I don't get funny looks from the lady-types because I'm wearing my camping gear to work.
The bad--Just like synthetics, it's all about spinning, weaving and thickness. While thick materials like denim are abrasion resistant, others such as t-shirts are not as strong.
The ugly--Cotton has no insulative properties when wet. While the wind wicks the top layers of water away and cools your body temp, the moisture on the surface sits there and further acts to transport heat away from your body.
Fall into a stream on a chilly fall afternoon and a person would succumb to hypothermia very quickly. Outdoorsmen call it "killer cotton" for a reason.
Also, have you ever tried smacking someone with a wet pair of jeans--ouch!
Wool
The good--Wool has natural oils in the yarn that aid water-repellancy. The inherent hollow spaces in the yarn create dead spaces that make very effective insulation. With the insulation and the water-pepellant nature of wool, wool is very effective at keeping you warm, even if the material is wet.
Wool is naturally breathable and has moderate wicking properties. Depending on the weave, wool can also make a good buffer against the wind. The same wool jersey that keeps me cool on my afternoon bicycle ride keeps me warm in the evening after I've drenched it with sweat and the sun has already set.
Wool is fire resistant and does not degrade quickly. If taken care of properly, wool will last many years longer than synthetics.
The bad--again, it comes down to textile manufacturing. I'm not going to wear wool clothing made from the same bolt of wool cloth that was used make the wool blanket in the trunk. For this natural fiber, it's all about what breed of sheep and type of wool, where it's from, how it's spun and processed and the final goals of the manufacturer.
Many wools irritate the skin due to the sharp kinks, bends and ends. This is due to the type of wool and the processing. Finer wools are nearly "itch-free" but are more expensive (ie, cheap import knockoffs are just cheap knockoffs, same with the synthetics).
In colder climates, people wore wool for generations. Our armies wore wool uniforms into battle for years. The same wool that kept them warm in the cooler climates caused many problems in the south and tropics due to heat related injuries. Luckily finer yarns and modern textile techniques have made wool suitable for most climates.
The ugly--Depending on the type of wool, there is often certian precautions in handling it. Sometimes the material is wash and wear with cold water, but others may be more intensive in their care.
While tightly woven wool is somewhat abrasion resistant, it is not as good as denim or synthetics especially manufactured to be abrasion resistant.
Quality wool that has been properly spun and woven will be expensive, often as much as or more than the synthetic equivalent.
Silk
I have a few observations based on my silk baselayers.
The good--Silk is lightweight, very strong, breathable and wicks moisture. It feels very good on the skin and has good insulative/cooling properties.
The bad--There are many precautions in the care of silk. I have little knowledge of the abrasion resistance of silk but I am guessing that it would not make a great work uniform.
The ugly--It is very expensive.
Leather
The good: Highly abrasion, water and wind resistant, flame retardant, and looks cool.
The bad: Expensive and you need Astroglide to get into a pair of tight leather pants /ubbthreads/images/graemlins/wink.gif
The ugly: No real insulative properties by itself.
So if you're venturing outdoors, we're left doing what every outdoor instructor has told us for years in moderate climates--dress in layers. Hopefully something trendy as you need style points to progress in this game.
