There does seem to be some regional differences with underwear styles. In my earlier post I mentioned that here on the east coast, when I was in college, tighty whities still reigned supreme among college guys, although colored briefs and bikini briefs also where making some headway. Boxer shorts still were rare EXCEPT I had several college friends from California and they all wore boxer shorts. It seems that the boxer shorts rebellion had a head start out west.
More recently, perhaps 10 years ago, a young man that I know went to the U of Tenn. He was a country boy at heart, liked farming, liked hunting and fishing, and I think this influenced his decision to go to U Tenn. He did not wear tighty whities. He quickly made friends with Tennessee country boys who shared his interest in hunting and fishing and within a couple of weeks he went on a weekend fishing trip with the guys. He reported to me that ALL of the guys wore tighty whities, he was the only one not wearing them. So he went out and bought some tighty whities for himself and wore them from that point onward.
Like me, he will wear boxer shorts for lounging around or just casual clothing, but his standard underwear now are tighty whities.