The LA and I saw a product of Fashion this evening: a young person wearing jeans which a) had a beltline below the buttocks and b) were so tight they must have required talcum powder to don. Apparently, these days, boxer shorts (of the old-fashioned, woven-fabric-and-elastic-waistband type) are no longer considered "underwear". I disagree with this, but that's mainly because my preferred underwear is that type.
However, I had a think about it, and functionally, it's not underwear for me either. I may not have it on display, but my boxers exist more to provide a consistent, non-chafing lining for the upper part of my trousers. For some years, I have been of the opinion that the best approach to underwear is to get as close to commando as possible. At Faire last Spring, I discovered that boxers are functionally equivalent to commando, a practice which is definitely less than pleasurable, since one is effectively dressed as an item of furniture in a hot environment. When one is sweating profusely, some figure-hugging is preferable to prevent chafing, if one must confine oneself in clothes.
However, in general, I prefer to minimise the irritance of my clothes, and so I wear boxers as the best option. Denim chafes.