A thread at BackpackingLight on boxers vs. briefs.

Something else I learned the hard hard way: regular old briefs ain’t made for walking long distances. They get all knotted up down there and end up chafing the hell out of that soft tissue on the inner thighs. Now whenever I hike more than six miles or so I always make sure I’m wearing some of those snug-fitting boxer-style undies.

Undies are like shoes: Never scrimp on cost/comfort — you don’t want those precious body parts rubbed raw.