(MONEY Magazine) – This winter you could decide to fight back against the cold by getting yourself a big down parka, which will keep you nice and toasty--so long as you do very little in it. Because if you exert yourself in any way, you're going to perspire, and while big down parkas are great at keeping heat in, they're generally lousy at letting moisture out. What usually happens is that you wind up clammy and, ultimately, cold.

For clothing better suited to physical activity (from chopping kindling to just going for a walk around town), you're going to want to take advantage of the kinds of materials hikers and other outdoorsy people have been using for years. Not that picking out the right gear is easy: The warmth and comfort that outerwear companies offer today comes in a multitude of shapes, fabrics and sizes--and at a price.

The key to comfort is in layering garments. The modern outdoor wardrobe consists of three layers, commonly called outer (weatherproof shells), mid (sweaters and such) and base (long underwear). Each performs a specific function while interacting with the others to keep you warm, dry and outdoors long after your down-parka-wearing partners have retreated to the living room to collapse in damp, shivering piles.

To determine what works--and what doesn't--I tested dozens of garments over a capricious winter in northern Vermont, which is where I live and where I've spent much of the past 20 years as a hiker, backpacker and elite-level cyclist. What follows is an opinionated look at the latest (and one surprisingly old) outerwear technologies.

THE OUTER LAYER Your first line of defense against Ma Nature's worst fits.

What it is A layer that keeps out rain and snow but also lets perspiration evaporate. You have two choices, hard shell and soft.

Hard shell For many years, this was your only option: a thin, crinkly jacket you'd throw on in driving rain or over a bunch of layers when the snow was coming down. Gore-Tex is the classic and almost-ubiquitous hard-shell material, but there are now many other products that do basically the same thing. A good choice is Mountain Hardwear's Confluence Parka, which has a hood that can fit over a thick wool cap, as well as a drawstring liner that keeps the cold stuff from blowing in. When the weather is truly foul, go hard shell--nothing else will keep you dry.

Soft shell This new category of outerwear is based on soft, stretchy fabrics that are water-repellent. Not only are soft-shell jackets more comfortable than hard shells, but they also "breathe" better, allowing more water vapor to escape during exercise, which means that you stay drier and warmer. Sounds great, huh? It is--mostly. A prime example is Cloudveil's Switchback Jacket, which is less than half the weight of the Confluence hard shell and breathes better than Lance Armstrong in an oxygen tent. Just stay out of downpours: While soft shells can fend off modest showers, a hard rain will soon soak through.

The MONEY Pick Soft shells are great, but it only took one surprise thunderstorm to convince me that unless you live in Arizona, a hard shell must be your go-to outer layer.

THE MIDLAYER Sandwiched between the outer and base layers, the midlayer is your chief insulator.

What it is Oftentimes, a fleece jacket or wool sweater. Midlayers usually aren't waterproof; that's what an outer layer is for. Without a midlayer, you might stay dry, but it'll be a cold sort of dry.

Wool Wool keeps you warm even when it's wet, doesn't retain body odors and holds up to years of abuse. And you probably have a wool sweater in your closet already. The only real downside? Wool sweaters can be kind of bulky--most backpackers and mountaineers prefer something that can be stuffed into the corner of a bag. If space conservation isn't a major concern, check out the Ibex Hooded Shak shirt. It features a close-fitting hood that will keep your head warm and a dense, insulating weave. It's also not too outdoorsy-looking, making it more versatile than other gear.

Fleece It's been more than two decades since the synthetic fleece pullover was introduced, and there's been nothing but steady improvement ever since. New fiber technologies have allowed manufacturers to create shirts, pullovers and jackets that are nearly windproof (which used to be a weakness of the material), incredibly light, easily packable and super warm. What's the catch? There isn't one, really. Modern fleece is so good, there's no excuse not to add some to your wardrobe of outdoor apparel. My favorite fleece is Patagonia's Synchilla Off-the-Grid Jacket. Its tightly knit construction helps keep icy winds at bay, which means you can wear it as an outer layer when the weather isn't absolutely frigid.

The MONEY Pick If you can have only one, it's gotta be fleece. It's just too practical. Still, don't overlook the capabilities of your old wool sweaters or the classically beautiful Ibex hoodie.

THE BASE LAYER Arguably the hardest-working layer in your arsenal, the base layer has to keep you both warm and dry.

What it is Basically long underwear--but made of newfangled wools and synthetic fibers that dry in a snap.

Merino wool Conventional wisdom says that wool must itch, but merino wool, an ultrafine, ultrasoft fiber, can be more comfortable than cotton. Merino also has natural antimicrobial qualities, so--unlike some synthetics--it won't serve as a repository for your BO. Wool also does an excellent job of wicking sweat away from the skin. SmartWool's Vortex Crew is ridiculously soft and cozy, and looks worlds better than most long underwear. Downsides? When you heat up, wool base layers can feel kind of sticky. And jeez, they're expensive: While SmartWool's shirt costs $85, a quality synthetic base layer can be found for $30.

Synthetics All man-made base layers are hewn from petrochemical-based fibers that wick away sweat and dry quickly, but each manufacturer calls its material by a different name, making things confusing. The synthetic garment I like most is REI's MTS Long-Sleeve Crew, which is incredibly light, keeps you dry as a year-old wishbone and won't break your budget. But unlike merino, synthetics quickly pick up a funk. And some people say they have a plastic feel to them.

The MONEY Pick It's a tie. I wear merino in frigid weather or when I won't be able to wash it soon, but when the sun's blazing, synthetic rules. Wool can feel cloying in warmer conditions.