Yes indeed, there are some, uh, newer materials out there. So many that it can be confusing to choose. But the good news is that they're really all pretty good. I must have five or six different brands and styles of long underwear, and aside from the weight, I probably couldn't tell the difference if you cut them all in half, sewed them together, and put them back on me so that left is Brand X and right is Brand Y.
Having said that, I generally don't wear silk or wool. Silk is fine, but kind of expensive, and best as an insulation when you're not going to be working hard, as it's not as good as synthetics at wicking sweat. Wool is great stuff, but expensive. An example of modern wool underwear would be Ibex's Mansfield Jersey ($98). It's very soft, washable and equally comfortable as a base layer or top. Very nice, and would likely last you until you decide to buy new long underwear in, oh, 30 or 40 years. Actually, that's true - I have a Woolrich wool shirt, the Buffalo shirt, that I bought in 1975. And aside from the concrete specks on it from an outdoor project a few years back, it looks remarkably like new.
Otherwise, I'd recommend one of several so-called "midweight" synthetic long underwear sets. These wick moisture beautifully and in the newer versions generally resist odor buildup well (that has been a problem with some synthetics). One example: Marmot's Women's Midweight Crew top ($37). Another: Patagonia's Women's Capilene Midweight Crew ($38). A good bargain alternative is REI's MTS Long Sleeve T for women ($22).
When skiing here in Washington, I use the midweight stuff as my only leg layer, with an uninsulated shell layer over it. For my torso, I start with the midweight then add either a light fleece layer or a synthetic-fill sweater. Any of the above will serve you well.
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