For me, tighty whities and short type boxer briefs (trunks) are equally instant turn-ons. However, they absolutely require a certain type of body to wear them which is the key.
To look good in tighty whiteys, the focus is placed on the word, tighty. Those poor briefs must be packed as if it was about to explode.
To look good in boxer briefs, same as tighty whities. Though, nice and big legs would definitely be emphasized better than briefs. To each their own!