Still, today's superlight down sweaters, such as the Moonstone Lucid ($160; www.moonstone.com), have plenty of uses. They don't weigh much more than a T-shirt and pack down to the size of a softball, yet are as warm or warmer than a bulky fleece jacket. And they're wonderful layering pieces because the nylon face fabric slides easily beneath a Gore-Tex jacket or something similar, at which point you are both warm and largely waterproofed.
The Lucid is a really nice piece. It uses extra-fluffy 800-fill down, and has a polyester shell that is treated for water-repellency. Polyester also absorbs less water than nylon, so it's a very fast-drying material should it get damp. And, the thing weighs only ten ounces in the medium women's size.
A similar piece would be Patagonia's Down Sweater ($159; www.patagonia.com). It uses 700-fill down, weighs a whisker less than the Lucid, and has a nylon shell that's treated with Patagonia's very good Deluge water-repellent coating. Still, its specs aren't quite as nifty as those of the Lucid. And, if price is the kicker, L.L. Bean sells its Mountain Guide Down Jacket—which I'd view as more of a heavy down sweater—for just $99 (www.llbean.com). It's a steal.
For more winter-worthy parkas, read "Cold Play" from the November '04 issue of Outside.