Easy choice for me - BOXERS. 6 years ago I discovered boxers after wearing briefs all of my life. It took me a month to get used to boxers, but there was no looking back afterward. I no longer have to deal with the crotch seams of briefs pulling against my torso; no longer have to deal with my goods needing constant adjustment from being confined. It feels great to never wear snug garments on a daily basis. It feels nice when my good swing to and fro.
When I wear my cycling bibs or shorts, I'm reminded of how it feels to wear sung shorts. I can tolerate it while I'm on the bike. As soon as my ride is over, I can't wait to change into something loose and comfy.