May I cheer?
In my fantasy based fanfics, my characters wear (or eschew) smallclothes. I seriously doubt elves would be partial to boxers. They'd be awfully bulky under those tight little breeches, after all.
Now, in a roleplay I'm doing with a friend, where my elves have taken up residence in Tokyo, they have discovered boxers, fundoshi under their formal kimono and hakama, and in one memorable instance (but we love him anyway) pantsu.
In my case, I've never liked the basic brief-style underwear for men. I keep thinking of the way they're referred to as tighty-whiteys, and there goes the mood for me. Boxer briefs are better, though, especially those short-legged little ones that Calvin Klein had all over billboards everywhere.