I love Underarmour Boxers.

Not the super compression fit shorts they make... the boxers. They rock.

And they are easily washable, and they dry in like 30 minutes.

I'll often go on long motorcycle rides intersperced with hiking... Underarmour stuff lets me pack really light... one set of socks, one pair of boxers, one undershirt. Wash that stuff every night, and everything else on top of it, can go for days and days.