All my life it's been briefs for me. I tried boxers once, but I need the support briefs give me keeping my equipment in the right position. It may sound funny, but I don't like having to 'arrange' myself in public... I've known some women through the years that couldn't figure out why guys do that (e.g. have to adjust themselves), but of course they've never had to deal with 10 lbs of untamed trouser-snake. 😛
(Sorry, couldn't resist... really, though, it was helpful, especially in my teens, when my equipment seemed to have a mind of it's own. Having everything 'in place' at times like that can avoid embarrassment, or at least it helps a little...)