Obviously I am not a guy, so the specs will vary some, but I have been very happy with merino wool briefs by icebreaker. I wore synthetics by Ex officio for several seasons and while they dry quickly they get a funk after a day or two. Wool is nearly stink free, and if I bring a spare pair along I can wash one in a creek and dry them out over the brush in an hour or two. I won't wear cotton or synthetics in the field again...