I've been watching this discussion for a while and thought I better add my voice.
I grew up with briefs usually blue, black or striped. Boxers were for sleeping in (again blue, black, striped or checked). Still kind of works that way.
Leading up to the birth of my son I read somewhere that Steve Irwin (Crocodile Hunter) Wore boxers for 3-6 months prior to conception to make sure he had a boy (lower temperature sperm etc) and also that you have to do 'it' a lot around ovulation because the boy sperm don't survive as long as the girl sperm....so you are basically flooding the area with sperm to give the boys the best chance of getting there first. Sorry if that is TMI. Anyway it DID work in Steve's and my case ..... maybe it is an Aussie thing. Anyway my point is that for that 3 months, for the first time in my life I wore boxers all the time. And it just about took me that long to get used to it.
Anyway so now, like Will, it depends on my mood or what I am doing. In summer I nearly always go commando because frankly it does get damn hot down under. I also had a bee in my bonnet about circulation for a while.
When I do wear briefs I wear Bonds GuyFronts. You probably don't get them in the states. They are very comfy (no seams) and kind of a modern twist on the old 'Y' fronts. Except the fly on the front is really only for show and form. They are pretty low cut and the fly isn't really functional.
I really only wear boxer briefs or trunks (that my wife has bought me) for those special occasions and they don't stay on long anyway.
More than meets the eye!