I recently picked up a pack of these at Target on sale:
Hanes Mens ComfortBlend Dyed Brief | 7500P4 or # 24344

It's the first time I've seen Hanes underwear that wasn't pure cotton, and was advertised to be both quick-drying and moisture-wicking, without costing a whole lot more than their regular underwear. I was wearing supposedly quick-drying underwear when I got drenched by a storm two weeks ago, but it absorbed so much rain water than it didn't dry all that quickly. Will let you know if I have better luck with this new Hanes.