Generally speaking, wool and synthetics keep you dry through different mechanisms. Synthetics are hydrophobicthey hate water. So they keep you dry by forcing the stuff away from your skin. Some of the more exotic ones have one kind of surface on the inside, another on the outside, to expedite the process. That's what Power Dry does in pieces such as L.L. Bean's Polartec Power Dry Midweight Crewneck ($32; www.llbean.com).
Wool, on the other hand, actually soaks moisture up, then slowly releases it through evaporation. Icebreaker claims that one of its pieces can absorb up to one-third its weight in moisture without feeling clammy, because a natural covering on the wool fibers shields the wearer from moisture. Wool works particularly well in situations where you just can't help getting wet or sweatyit's much warmer, in my experience, than synthetics in those cases. The downside is that it can take longer to dry.
I can't comment on the smell factor, except to say that after 80 days, nothing is going to smell particularly daisy-fresh.
So, yeah, get some wool underwear. From personal experience I can vouch for the quality of Icebreaker pieces, but SmartWool also makes some stuff with the same basic merino wool (its midweight long-sleeve Solid Crew, for example: $65; www.smartwool.com), and REI even has some house-brand stuff under its MTS, or Moisture Transport System, moniker (also $60 for a midweight long-sleeve crew; www.rei.com).
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